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BULLETINS
OF
AMERICAN PALEONTOLOGY
VOL. XXVIII
got edaet patsege > e a ? JUL 25 1944
13,96! Sa we
CONTENTS OF VOLUME XXVIII
Bulletin No. Plates
109. Studies of Paleozoic Nautiloidea I-VII
ByeRouSSe ave Hoshi LONGI esas eee ne Sat 1-6 110. Three Forks Fauna in the Lost Rives Range,
Idaho
By Ewart M. Baldwin _____.__ tre i 111. Contributions to the Paleontology of NeceooN.
Peru. Part VII. The Cretaceous of the Paiti
Region
Bye Axely AcwOLSS Ont fas fas seake Rae oe BES Se ee 8-24 112. Notes on Eocene Gastropods, chiefly Claibornian
Bye ktarheninenaye.e Ws) allie ries s= eae ne 25-26 113. New Foraminiferal Genera from the Cuban Middle
Eocene
By W. Storrs Cole and Pedro J. Bermudez __ 27-29 114. The Larger Foraminifera from San Juan de los
Morros, State o* Guarico, Venezuela ByaC Ms bramine Gaudin ss eee 30-34) 1 a0 (eben ate ol elle ie te AE Ie) se el recy OCS
Pages
1-140
141-158
159-304
305-330
331-350
351-404 405-412
_ Patgontorocicar Rescarcu |
CONDENSED TABLE OF CONTENTS OF BULLETINS OF AMERICAN
PALEONTOLOGY AND PALEZONTOGRAPHICA AMERICANA*
BULLETINS OF AMERICAN PALEONTOLOGY
Volume 1. €Nes. 1 5)'54854pp.; 32 pisn se ee Se eS ee Mainly Tertiary Mollusca, II. (Nos. 6-10). 347 pp., 23 pls. - = Sree O08 Tertiary Mollusca and Foraminifera, Ap aleomoie ‘faunas. Hil. (Nos. 11-15). 402 pp., 29 pis... = ZL ASS COND Mainly Tertiary Mollusca and Paleozoic nettione and faunas. IV. (Nos, 16-21). 151 pp., 26 pls. za = 2 D.00
Mainly Tertiary Mollusca and sections of Paleozoic sec- tions and faunas. V. (Nos. 22-36). 457 pp., 68 pls. . 8.90 Tertiary fossils mainly Santo Domingan, Mesozoic ‘and Paleozoic fossils,
VI.” (No. 31).)) 268. pp.;.59 pls. °: NEP Ny ae ee a a Pear eee NO Claibornian Eocene pelecypods. Vil... (No. 32} 729 py:, 29 ls. Ale Sek ANU Si 12.00 Claibornian Eocene seaphopods, gastropo as and cephea loz pods. Vald.< (Nog.33-86). 2357 pps, Wh6 plsyoic Oe a Ce see Gee 00 Mainly Yertiary Mollusca. IX. (Nos. 37-39). 462 pp., 35 pls. 2 i 7.00 Tertiary Mollusca mainly from Costa Rica. X. (Nos, 40-42), 382 pp., 54 pls. aeons 8.00
mm
Tertiary forams and mellusks mainly froin reinidad and
Paleozoic fossils. : XI. (Nos. 43-46). 272 pp., 41 pls. \ fy L508
Tertiary, Mesozoic and Paleozoic fossils mainly from Venezuela. XH. (Nos. 47-48), 494 pp., 8 pas. ee ee a GOO
Venezuela and Trinidad forams and: “Mesoz z0ie inveHees brate bibliography.
XHI. (Nos. 49-50). 264 pp., 47 pls... = kes .. 6.00 Venezuelan Tertiary Mollusca and Tertiary Mammatia.- XIV. (Nos. 51-54). 306 pp., 44 pls. — : : 6,59
Mexican Tertiary forams and Tertiary mollusks of Peru and Colombia.
* Complete titles and price list of ai} numbers may be had on appliea-
sion. All volumes available.
BULLETINS OF
AMERICAN PALEONTOLOGY
Vol. 28
No. 109
STUDIES OF PALEOZOIC NAUTILOIDEA I-VII
I. TISSUE REMNANTS IN THE PHRAGMOCONE OF RAYONNO- CERAS II]. WERNEROCERAS IN THE DEVONIAN OF NEW YorRK III. A GONIOCERAS FROM VIRGINIA IV. INVESTIGATIONS OF ACTINOSIPHONATE CEPHALOPODS V. NEw ORDOVICIAN CEPHALOPODS FROM EASTERN NortTH AMERICA VI. Some SILURIAN CYRTOCONIC CEPHALOPODS FROM INDIANA WITH NOTES ON STRATIGRAPHIC PROBLEMS VII. ANNULATED ORTHOCERACONIC GENERA OF PaLgEozorc Navu-
TILOIDS By
Rousseau H. lower University of Cincinnati Museum August 10, 1943 Paleontological Research Institution
Ithaca, New York Wi Saet
AUG 19 1943
LipRan*
1396/
CONTENTS
Text
Page
I. Tissue Remnants in the Phragmocone of Rayonnoceras 5 (Bp o-18itext. net pli pars:)
PNY OSS EL eREY es = eee tS 5
IIGANERECONGRDICOUENICCY py A Se ee 5
IRON NOCCNAS). eee Ee 10
Reeth otal By Owe rsp Tou sn eee ee 12
TRUE TEEN aN CLS ee ps ee ee ee ee 13
II. Werneroceras in the Devonian of New York 14
(Pp, 14-21 ple 15 pars.)
PNT OER TEENIE i FE ree ee ee 14
TEETER eYOyG lO CA EAUCa GN gel Se NE a dE ere 14
GHA STR EOIN JOOS) qe 15
Werneroceras plebiforme (Hall) —.— 19
TER eG CITING CS pames cem c ae aae e oe en a 21
it AGrGonioceras; from) Virginia 22 ee 21
(Pp. 21-29; pl.-2, pars.)
PA SiG Trek Ct aio ee ee ee 21
Niaz GNU C10 ramen eae ene a ae Meese ee Se ee yaa
Distribution of Gonioceras in America ae re eee eee 22
Goniocerds hubbardieilower. WSs eee ne 26
1Beyeh enratel ok She cs esee P See e ee n Se eeee ee 29
IV. Investigations of Actinosiphonate Gehalnnide pA Wee retire: 50 Mes eek 30 (Pp. 30-67; text fig. 2; pls. 2-6, pars.)
INUONETRE Oe A Se IN al ee ee 2 ee 30
Aa CU 1 Oe er ed ee 30
Structurelof actinosiphonate: deposits) = = ees 35
Chazyan actinosiphonate cephalopods — === 37
Walleounocenas Iloyyeie iy (Gin; Ge 43
We. lexcnyiayouen Ion sehes dale S105 eee ee ee
We obesum™ Blowers ie Spa 46
War relonogad tion eit als Sion eee a ee 47
V. cf. seeleyi (Ruedemann) aie BOE ees en 48
NV erfSH) 00 a Ua Se a I I oe ae 49
Wires. eau 50
Bipectinate eaee enone deposits ars ioe pees. Mee ee 51
(2)
Actinomonphia) Hilowien,. i) Seine Br re 53 AS pupar Hiloweie ns (S[0).) es ae 55 Actinosiphonate deposits of Archiacoceras ha tS 57 Discrete sanmulosiphonabes depOSits sss ee 62 GOEL UTS OTT Sen 64 References ——... oN 2 ee de Se 67
V. New ra ial Coanalonde ae Rastern North America ____——~Ss 68
Vi.
Vil.
Pp. 68-82; text fig. 3; pls. 2, 4-5, pars.)
Pe ee Bronn? 0-224 2 26 2 eee 68
Actinoceras arcuanotum Flower, Nes). = ee 68
lDoralbaocereaich IMIG Rees ay FN, oY
E: platyceroides; Mlower wnt Sp.) eee 70
Hotriptesocerds Hlower nin Celie a ee 71
KH, muinutum) Wlowenr iSpy = Ral
Graciloceras low ersns ei enise eee eee 72
G_ omesicomnuirmee byl Ose iiyetlsi Ss ee ee eo 74
Centrocyrtoceras) Hoerstey = =) ee 75
CA mozolaimhlowieranees pe ee ook 75
Trocholites!:Conmady 22 es ee a eee
UU aebieeleiaavenaiant IMO eieyeioly SiO) eee ee 79
Teeracilis(Mlowern.Sp: -2)... =e een
Refierencess === ed ea eee sere {372 Seme Silurian Cyrtoconic Gann clennas Be qediees ee notes on
Stratigraphic, Problems] 2222 2.332222 eee 83
(Bp83-101; Pils: me is fpars.)
Abstract: 225. -- eV = Sse ee ee eee 83
Introduction Deis Se Ss Ypres ey 2 putea, (38)
Silurian cephalopod faunas. in . Indiana Be OD
Pentamenoceras, Hyatt 22s = ea ee _ 89
12, @unrmaersh IMO Wee, Thy Bids 2 a
Netrameroceras) blyatt ==) eS ee 95
TT. faberiMlower) no 7S. 2) sD
Maumello.cerals Eilowwienean rien 2 erie eset 97
Ibe) wlio easy ION eie5 ANG Soy Se Se ee OD
References) == = : SE ote 100
Annulated Grihocemeente Genus Be ‘Palooreie Nautiloide ts 102
(Pp. 102-128.) AND ISIER AGG 2-22 2a rae a eee a eee ( Introduction ee eee ee eee oa ae Doe ee 102
Proposed generic names oo Genera proposed by Shimizu and. Obata ee eee ee il:
Jaeweonilhy (ShonyacoereeN anole) Boa Sa cee oe 110 Ramnuilyae Pam (elilloic etre llc ce eae eee 111 Hamiullysa Cyclo erties eee 111 Famanll yak sikcin(ore er ait clea ee ilar
Genera proposed by Shimizu and Obata for shells of the external aspect of Spyroceras. (Spyroceratide and Ham-
melloceratida Shimizu, ‘and "Obata ilit Hospyroceras 2 ae a eee eee = oe ee ital Hypospyroceras «22 Se eee 113 Subspyroceras 2--2< = 5: ee 113 Anaspynocetas; 223 = ee ee ee 114 Gedarvillocerds” 2. 2 ee ee ee 115
Corkvocerac: sae = 116
(Roman
Plate 1.
DeMeedirrntryy @\1'T oe erga ae ate ee 117 ZO TRGE ISO COREA S iy ene ea er ree eo See eee ee 118 Genera of annulated cephalopods with transverse markings OAC MOG Joni MSeuivoaAbl Gl (Oona 119 BamualyanCy.cloceratid zee =< ree ee ee 119 TE eraai ivan Kalina OC ts Ae Cl ae ee 120 Psecudesk:imoc era sy see ses See ee ee 120 KO Peni era Ss ares sae eee ee en ee ee 121 Summary of Paleozoic annulated cephalopod genera —.. 121 Phyloseneticgnote sip se eee ee ee ee ee 125 EUG TCT C TIC CS ee we ie ek a eee ee ey Su AG
Plates
numerals refer to the number of the paper in this series to which the figures on any one plate pertain.) Rayonnoceras (I), Werneroceras (II), Tetrameroceras (VI) 130
Plate 2. Pentameroceras (VI), Valcouroceras (IV), Gonioceras (III), BAN GIEINIO. GE Ta Saps(OV)) nee re ee ee 13 Plate 3. Tetrameroceras (VI), Actinosiphonate cephalopods (IV), 134 Plater Walcounoceras, (live) Graciloceras) (Vi) ee 136 Plate 5. Actinosiphonate cephalopods (IV), Ordovician and Silurian cephalopodsey GV; avi) aa eee ee ee ee ee 138 Plateso, siphuncles|of “Archiacoceras, (iV) = eee 140 Text figures lle SBatciBil SeCoin, Gir INEATOUNO ENS 2 9 ZAMOLLUCtUEe OL actinosiphonatey (ep.o sis sem eens enn n 40 SmGraciocerasmlongealdomuUm sHLowers ene nese) eee 73
I. TISSUE REMNANTS IN THE PHRAGMOCONE OF RAYONNOCERAS
ABSTRACT
A small Rayonnoceras from the Chester of Indiana which was buried in its normal life position is described. Study of sediments entering the shell indicate barriers which have since disappeared and are represented by eal- cite. Thin bands of calcite mark a peculiar but characteristic pattern in the phragmocone and are interpreted as calcified remnants of the partially distorted cameral mantle. The specimen represents a new species and is the first record of the genus east of the Mississippi. Other American spe- cies of Rayonnoceras are briefly reviewed.
INTRODUCTION
A specimen representing a new species of Rayonnoceras from the Chester of Indiana is mainly of interest for the evidence which it presents of tissue in the camere at the time of burial of the shell and the infiltration of inorganic materials. This tissue affected the invasion of sediments and influenced the deposition of calcite in the shell cavities to which the sediment failed to penetrate. Previously the writer (Flower, 1939, pp. 45-51) came to the con- clusion that the cameral deposits of orthoceracones were secreted by a cameral mantle, and traced the probable origin and develop- ment of that tissue. At the same time a specimen on which the cameral mantle was preserved in place (pp. 164-165, pl. 7, fig. 8; pl. 8, fig. 19) was figured and described and mention was made of the specimen described here (p. 46) in connection with the evidence of cameral tissue present at the time of burial of the shell. Subsequently the study of a unique specimen of Leurocy- cloceras (Flower, 1941) presented a remarkable case of the pres- ervation of the large blood tubes which were developed in the cameral mantle of that genus, thereby demonstrating that the vascular system may pass directly from siphonal to cameral tis- sue. The present study is significant mainly in recording a rather different mode of preservation of cameral tissue and indicates strongly that hitherto unexplained structures in nautiloids may be the result of the retention of cameral tissue in a more or less altered state.
BuLLETIN 109 6
o>
In order to demonstrate the effect of tissue upon the invading sediments it is first necessary to consider briefly the orientation and history of preservation of the specimen concerned. The shell came into my hands in a block of limestone showing good bedding planes. Study of a section through the protruding adapical end of the shell showed that the conch lay with the ventral surface close to one plane, the dorsum close to the other. Closer inspec- tion revealed that sediment was confined to the ventral portion of the shell, while the dorsal portion was occupied by calcite repre- senting a complement to the incomplete internal mold formed by the sediment, Further, this was adequate to show that the conch had come to rest upon its ventral surface, as is common among actinoceroids, as the result of the concentration of heavy cameral and annulosiphonate deposits on the ventral side of the shell.
The sagittal section of the specimen (text fig. 1, and Pl. 1, fig. 1) reveals more of the history of this shell. The living cham- ber is lost, the adoral septa are somewhat broken and the connect- ing rings are completely destroyed except where they are rein- forced by heavy annulosiphonate deposits. These facts indicate that the shell was subjected to considerable damage, probably by wave action, previous to its burial. After it came to rest on its ventral surface, sediments entered through the siphuncle, and settled into the ventral portion of the cameree. The siphuncle is not filled completely by sediments. Close inspection reveals that the sediments do not quite attain the septal necks on the dorsal side. The dorsal line of contact of sediment and calcite is some- what irregular, but approximately parallel to the bedding plane, and the upper portion of the siphuncular cavity is not filled. As a result, casual inspection of the section fails to give a correct impression of the strongly cyrtochoanitic condition of the siphun- cular segments on the dorsum.
Were this all, the specimen would be an interesting but ex- tremely typical example of the development of an incomplete in- ternal mold in an orthoceracone. However, at one point a clear break is shown in the dorsal wall, which has permitted sediments to enter a single camera from above. Under normal circum- stances the sediment entering from above would be expected to sink and mingle with that entering through the siphuncle, but here
7 Tissuzr REMNANTS IN RAYONNOCERAS: FLOWER 7
something has happened to keep the two masses of sediment apart, for they are widely separated by a mass of calcite. This calcite, by its position must represent the inorganic filling of a space for- merly occupied by some substance, now missing, which ob- structed the invading matrix. A tissue is at once suggested, sub- sequently decaying and leaving a cavity to be filled in geodically by calcite. Further, from what is known of the presence of tis- sue in the camere of cephalopods from other sources, this con- clusion seems the only logical one which can be drawn from the present specimen. It is not improbable that cameral tissues, be- ing somewhat protected in location, might persist in the shell after the removal of the visceral mass and the siphonal tissues. They would not be found unaltered, as was noted in Geisonoceras teicherti (Flower, 1939) but would probably be more or less sub- ject to decay which would cause them to separate from the shell entirely or in part, and might produce some very marked modi- fications in their original form, thickness, and areal extent.
If cameral tissue is present in a camera which has been in- vaded by matrix, it is quite possible that it may be found in a better state of preservation in less exposed camerze of the same shell. Inspection of more adapical camerze which are not open to the exterior through breaks in the shell wall, reveals structures to which no other explanation seems to be applicable.
In the inspection of these camerze four types of calcite can be observed. First, there is a dark, fine-grained calcite which has replaced original organic calcareous deposits of the shell. On the ventral side this has replaced the siphonal deposits, seen clearly about the three adapical septal necks and less clearly on the fourth. Also, close to the ventral wall, it has replaced the original cameral deposit, episeptal in this species. Equally def- inite in the specimen, though somewhat more obscure in the pho- tograph, are the cameral deposits close to the dorsal wall in the adapical two camer. The appearance of the original calcareous deposits in this section is very different from that of any of the
following types of calcite, which are therefore to be attributed to other sources.
8 BULLETIN 109 8
The second type of calcite consists of fine-grained, possibly cyrtocrystalline material, which forms a series of thin white lines. These lines occupy approximately similar positions in the adapical two camere on the dorsum, and traces of them in a somewhat dis- torted condition can be noted in the next two dorsal camere. Adjacent to the lines of white cryptocrystalline calcite are broad bands of white calcite, clearly crystalline, though composed of rel- atively small crystals. These separate the white bands noted above from the fourth type of crystal, and in places grade into the last type, which consists of darker colored coarse crystals of calcite.
_ The last two types of calcite represent the geodic filling of cavi- ties in the shell; here, as is usual in such cases, crystallization be- gins with numerous fine small crystals around the periphery of the cavity and ends with the deposition of coarse and rather ir- regular crystals at the center. However, the thin white lines re- main to be explained, and must represent the position of some substance which controlled the pattern of calcite deposition. The course of these lines is shown in text figure 1, though no attempt has been made to differentiate the two types of calcite which to- gether make up the geodic filling. It is apparent from the con- dition of the specimen that the white lines must represent a struc- ture which was present before calcite was deposited in the camere. Further, the form of the line suggests that it was a thin tissue, which, if stretched out, would approximately line the camere. The conclusion seems unavoidable that this represents a portion of the original cameral tissue which has become separated in part from the septa, to which it was originally attached, and was lying in a somewhat distorted condition in the camere. ;
The course of the line suggests this explanation more strongly when its details are examined and compared with conclusions reached on the form of the tissue from other data. At the adapi- cal end of the specimen (text fig. 1) the mantle line lies close against the septum, and continues along the cameral deposit and the dorsal wall of the camera. On the adoral surface a portion of this line has broken loose, and has slipped downward a little. Further, there is to be noted here a peculiar arching of the man- tle away from the ventral surface, also seen more clearly in the next camera orad. Continuing the line, a slight break is to be seen at the tip of the septal neck, also seen more clearly in the
9 TISSUE REMNANTS IN RAYONNOCERAS: FLOWER 9
next camera, Inasmuch as this is the point at which the connect- ing ring and enclosing tissue were attached, the break is to be expected precisely here. The tissue then continues around the septal neck into the next camera. It follows the margin of the camera to the tip of the next septal neck at which a break is again seen, this time a more conspicuous one. In the third camera the tissue remnant is less completely preserved, and its position is clearly modified by the sediment penetrating from above. Only a faint remnant is preserved in the next adoral camera.
The course of the white lines is not precisely that postulated previously for cameral tissue, but it must be remembered that in this specimen not only have most of the soft parts been re- moved, permitting the entry of sediment through the siphuncle, but the shell had suffered breakage, indicating some transporta-
Figure 1. Sagittal section of Rayonnoceras malotti Flower, n. sp. orient- ed with the dorsum up, the position in which it was buried. Original shell parts are in solid black. M—Matrix which has entered both from the adoral end of the siphuncle and from the break in the dorsal wall. C—Cal- cite occupying portions of shell not filled by matrix; infiltrated inorganic material. _B—Cryptocrystalline caleareous bands representing position of eameral mantle at time of burial and solidification.
10 BULLETIN 109 10
tion previous to burial. There is certainly ample opportunity for
dissolution of cameral tissue in this interval, and the retention of |
any trace of cameral tissue under these circumstances is remark- able. Apparently previous to calcification the mantle has been pulled loose from the adoral surface of the camera, and the lobe thus formed has tended to slump downward slightly. The be- havior of the mantle in this way seems to be characteristic ; not only is there indication of such folding, but there is a similar arching of an inorganic mineral deposit, though this time of chal- cedony, in the holotype of Harrisoceras orthoceroides (Flower 1939A) which appears to represent the same phenomenon.
Quite possibly the retention of cameral tissue is a much more common factor in nautiloids than has hitherto been supposed, Its presence has been suspected by the writer in the region surround- ing the siphuncle in several pseudorthoceroids, also in the cameree of holochoanites, where it has a somewhat different distribution. The field is largely an unexplored one, and one rich in possibili- ties:
Genus RAYONNOCERAS Croneis
The Actinoceroidea are essentially an early Paleozoic group, at- taining their maximum expression in the Ordovician. Some new types appear in the Silurian, but only two genera are known in the Devonian, Ormoceras Stokes and Metarmenoceras Flower, of which only Ormoceras is known to extend from the Lower to the Middle Devonian. (Flower, 1940.)
It is surprising, therefore, to find in the Mississippian and Pennsylvanian anew type of actinoceroid which appears both in Europe and America, the genus Rayonnoceras Croneis, which contains the largest known actinoceroids. The genus was for- merly referred to the Actinoceratide, but the writer has suggest-
ed (1940) that it might be placed in the Sactoceratide instead,
a change which is supported by some structural features and
which is overwhelmingly suggested by the range of the genera involved. ;
Schindewolf (1933) has differentiated Carbactinoceras which
ial TissuE REMNANTS IN RAYONNOCERAS: FLOWER TAL
was proposed as a new genus, though the author remarked that it might possibly be regarded as a subgenus of Rayonnoceras. The two groups are distinguished on the basis of the following characters :
Rayonnoceras Carbactinoceras Siphuncle broad, ventral Siphuncle narrower, subcen- Necks relatively long, not less tral than brims Necks shorter than brims Cameral deposits episeptal Cameral deposits episeptal and hyposeptal only
The status of Carbactinoceras as a subgenus seems more in keeping with the instability of these characters which vary con- siderably among the species and which strongly suggest com- plete intergradation between the two extreme types.
American species of Rayonnoceras.—Rayonnoceras bassleri Foerste and Teichert (1930) is unfortunately based upon a speci- men the label of which is lost. It is believed from the lithology and the resemblance to FP. solidiforme Croneis to be from the Fayetteville of the Upper Mississippian of Arkansas. Indeed, these two species, both probably from the same horizon and re- gion, are very similar. RF. solidiforme possesses septa which “ex- tend horizontally out for a certain distance from the dorsal side of the septal foramina, whereas in PR. bassleri they rise immedi- ately upward from the foramen.” (Foerste and Teichert, 1930, p. 210.) It might be noted that the remarkable course of the septa in FR. solidiforme is almost certainly the result of distortion of the specimen under pressure, as the same effect has been ob- served in numerous other cephalopods, always attributed to flat- tening. The other characters by which the species are separated are such as might possibly vary among different parts of the conch of the same species, and it is probable that the two forms may be conspecific.
R. buffaloense Foerste and Teichert is a small form, the holo- type obviously somewhat distorted by pressure but with strong- ly oblique sutures which are apparently original. It is from the Caney shale of Oklahoma.
12 BuLLETIN 109 12
R. girtyi Foerste and Teichert is a larger form with nearly straight sutures, and closely resembles FX. vaughanianum in size, but that species possesses more oblique sutures and siphuncular segments which are longer in proportion to their width. &.
vaughanianum (Girty) (see Foerste and Teichert, 1930) 1s a large species with a strongly eccentric siphuncle and oblique su- tures. Both species are from Oklahoma in boulders of the Caney shale regarded as of St. Louis age.
A new species from the Chester of Indiana is described below.
Rayonnoceras malotti Flower, n. sp. Plate 1, fig. 1; Text figs 1
The conch is orthoceraconic, slightly depressed in section, A fragment of a living chamber has a width of 25 mm. and a height of 23 mm. The holotype, consisting of a portion of a mature phragmocone, expands vertically from 16 mm. to 18 mm, in a length of 15 mm. There are seven camere in a length equal to the adoral shell height of 18 mm., but in the adoral portion of the region measured the camere decrease in depth from 3 mm. 0 2.5 mm., showing that this represents a mature phragmocone. The depth of the camer in the ephebic portion would be some- what greater, and their number in a similarly measured length slightly less. The sutures are not exposed, but are evidently oblique, as can be determined from the vertical section, the obliquity being equal to the depth of an ephebic camera. Where the height of the shell is 17 mm., the siphuncle is 5 mm. in diam- eter at the septal foramen, and is 2.5 mm. from the ventral wall. The connecting rings are destroyed, but their outline can be traced in the adapical part of the shell by the external outline of the bet- ter developed of the annulosiphonate deposits. The brim is twice the neck, the neck being .5 mm. in length. The area of adnation can be seen on the ventral side only, where it is much greater | than the brim, and extends halfway to the ventral wall of the shell.
Mural deposits are present in the camer of the holotype. De- posits of the siphuncle are typical of the genus, but not far enough
developed in the fragmentary specimen to eho the course of the vascular system.
us TISSUE REMNANTS IN RAYONNOCERAS: FLOWER is"
The species was evidently small, for the gerontic portion of the camere is retained in the holotype. The markedly ventral siphuncle and the obliquity of the sutures separate this species from all others. The closest relative appears to be R. buffaloense Foerste and Teichert, of the Caney shale, but in that species the septa are deeper, the siphuncle more central, and the camere much deeper. Our species is further distinctive for its small size.
Type.—University of Cincinnati Museum, No. 24078, holo- type.
Occurrence.—From the Chester of southern Indiana. Exact locality and horizon are unknown. The specimen came into my hands unlabeled, among miscellaneous material collected by Dr. E. A. Logan and his students, and was nearly thrown out. Dr. C. A. Malott has kindly examined the specimen and the block from which it was cut, and on the basis of lithology has tenta- tively assigned it to the Paoli member of the Chester. In spite of its fragmentary nature the specimen is of interest not only for the features of morphology and preservation discussed above, but in being the only specimen of a Rayonnoceras so far recognized in the Chester group of Indiana.
REFERENCES
Flower, R. H. 1939. Study of the Pseudorthroceratide. Paleont. Amer., vol. 2, No. 10, 214 pp., 9 pls., 22 figs. . 1939A. Harrisoceras, a new structural type of orthochoanitie nautiloid. Jour. Paleont., vol. 13, pp. 473-480, pl. 49. 1940. Some Devonian Actinoceroidea. Jour. Paleont., vol. 14, pp. 442-446, pl. 61.
Foerste, A. F. and Teichert, C. 1930. The actinoceroids of east-central North America. Denison Univ. Bull., Sei. Lab. Jour., vol. 25, pp. 201-296, pls. 27-59.
Schindewolf, O. H. 1939. Bemerkungen zur Ontogenie der Actineceroidea und Endoceran (Cephal., Nautil.). Neues Jahrb. fiir Min., ete., Beil.-Bd, 74, Abt. B., S. 89-113, 8 figs.
14 BULLETIN 109 14
Il. WERNEROCERAS IN THE DEVONIAN OF NEW YORK
ABSTRACT ei
On the basis of an exceptionally large and well-preserved specimen, the description of Werneroceras plebiforme 1s revised, — The species is regarded as occupying the uppermost beds of the Union Springs member of the Mar- cellus instead of the Cherry Valley member.
INTRODUCTION
The oldest ammonoid known from the Devonian of New York is IV’erneroceras plebiforme (Hall) which was previously report- ed only from a single locality, Cox’s ravine, at Cherry Valley, New York. The same exposures constitute the type section of the Cherry Valley limestone, though extending also into under- lying and overlying formations, During the summer of 1939 two exceptionally well-preserved specimens were found at Stock- bridge Falls, Oneida Creek, Madison County, New York. These specimens were in loose pieces, which were obviously from one of several thin limestone bands in the upper part of the Union Springs member of the Marcellus shale. In the spring of 1941 additional specimens were obtained, this time in place, in the up- permost of these thin limestone bands at the same locality.
This discovery establishes a new locality for the species, and suggests that actually it is probably much wider ranging than was formerly believed. That it has not been reported pre- viously 1s probably due in part to the fact that the shales under- lying the Cherry Valley limestone are usually exposed in cliffs, not suitable for extensive collecting. Further, the attention of fossil hunters 1s more generally directed to the more difficult but richer collecting of the Cherry Valley limestone rather than to the relatively barren layers beneath, which have a smaller and a not very spectacular fauna.
The new material is of further interest in that it supplies not only the largest representative of the species known, but also shows better surface features than any other known specimen, and indicates that the umbilical spines increase in prominence in the mature part of the shell, and are not confined to the early whorls as all previous descriptions would lead one to believe.
15 WERNEROCERAS IN NEW YorK: FLOWER 15
The find is of further interest in that it involves a minor but intriguing stratigraphic problem, as there is some question as to
whether the “Anarcestes bed” should be placed in the Cherry
Valley or in the Union Springs member of the Marcellus shale.
STRATIGRAPHIC POSITION
It may be safely assumed that WVerneroceras occurs at equiva- lent horizons at Stockbridge Falls and at Cherry Valley. In both localities the species is limited to a horizon certainly not more than 4 inches in thickness. Further, it occurs in a type of lithology, in fine-bedded limestones and very thin-bedded black shales, which are notable for the retention of fine stratigraphic divisions over relatively wide areas. The Cherry Valley locality has yield- ed a considerable suite of specimens from a single bed, sometimes so abundantly as to retain four individuals on a slab slightly less than a foot square. The Stockbridge locality has a less impos- ing record, but has yielded a total of eight specimens, of which five were little better than impressions, but all except two were collected from limestones in place, and are sufficient evidence to indicate that here also the }Verneroceras is a good horizon marker, though certainly less abundant.
On a strictly lithological basis the ]Verneroceras bed occurs in the limestone mass which overlies the basal shales of the Mar- cellus and which constitutes the type section of the Cherry Valley limestone. However, as is shown below, this section is atypical and differs from all other sections of the limestone in carrying a great mass of calcareous material which is elsewhere represented by Union Springs shales with thin interbedded lime- stones,
On a similar lithological basis the IVerneroceras bed occurs at Stockbridge Falls in the upper part of the Union Springs shales. The limestone layer which it occupies, there about three inches in thickness though varying from 1 inch to 5 inches and quite con- cretionary, is lithologically identical with at least six other beds of limestone occurring at intervals farther down in the section for a distance of about fifteen feet. Farther down, limestone bands be- come less concretionary and gradually increase in thickness until they blend gradually with the top of the Onondaga. Although
16 BULLETIN 109 16
IV erneroceras has not been found in the type section of the Union Springs shale, its horizon is doubtless represented there as at Stockbridge by the final limestone band of the Union Springs member.
The discrepancy in lithology between the type section and more westerly sections of the Cherry Valley limestone is largely re- sponsible for the apparent difference of opinion between the writer (Flower, 1936) in citing l’erneroceras from the Union Springs member, and Miller (1938) in citing it from the Cherry Valley member of the Marcellus. Clearly faciological changes are such that it is not possible to draw a precise boundary at the base of the Cherry Valley limestone on the basis of lithology which will be exactly equivalent in all sections. The matter is largely of academic interest, inasmuch as only a very small interval of the section is involved. More important, however, is the possi- bility of recognizing restricted horizons in this part of the section by means of the fauna.
The lower part of the Union Springs shale has never been sub- jected to sufficiently systematic collecting to permit any conclu: sions as to the possibilities of faunal segregation of minor ele- ments. The lowest part of the section which has come to the at- tention of the writer consists of the upper eight feet of the shale as known from Cherry Valley and more western localities. The fauna here is that generally considered typical of the Union Springs shale. Styliolina fissurella is dominant, Lunulicardium marcellense is abundant in all sections, though it extends over a considerable vertical thickness and is clearly useless as a precise horizon marker. A Bellerophon-like gastropod occurs, which at- tains considerable size particularly in the Cherry Valley section, and may readily be mistaken for the unfortunately little known Tornoceras which occurs in this part of the section at the three localities which I have collected most closely, Cherry Valley, Stockbridge and Union Springs. Less common is a large Pan- enka, aff. P. ventricosa, one of the few species which appears to continue into the overlying Cherry Valley limestone. All of these forms are found in association with the IVerneroceras at Stock- bridge Falls, where the fauna as well as the lithology suggests the Union Springs and not the Cherry Valley.
17 WERNEROCERAS IN New York: FLOWER 17
The thin shale band between the I!’erneroceras layer and what I propose to regard as the base of the Cherry Valley limestone, accepting momentarily the lithological boundary as developed from Stockbridge Falls west to Union Springs, seems to contain no diagnostic species. In it occur large concretions, though they are never continued to form a band of limestone in these regions. The Cherry Valley section is exceptional in this respect.
The lower member of the Cherry Valley is a massive block of limestone which rarely contains cephalopods. Lithologically it is identical to the upper layer, though inclined to be finer grained and less crystalline at the base. This layer I have found to con- tain Aulopora, sp. in great numbers, which I have never observed anywhere in the upper layer. It also contains abundant Proetus haldemani Hall, Leiorhynchus limitare, and several small gastro- pods. Marcrochilina ononcagaensis Clarke, I have found only in this layer, but the species is not common and may occur in the overlying cephalopod beds. The Aulopora, abundant Proetus and small gastropods seem to be excellent criteria of this layer. It also contains a large thick-shelled Coleolus, which is apparently closer to the C. crenatocinctum Hall of the Onondaga than to the species which he described from the Cherry Valley limestone, C. aciculatum, a smaller form with a curved apex, and no known surface ornament. The only cephalopods which I have found in this bed consist of inadequate fragments of Agonia- tites. The shaly partings which separate this from the overlying mass of the Cherry Valley limestone sometimes contain poorly preserved Agoniatites, Although these specimens have been carefully examined with a comparison with A. nodiferis in mind, they fail to show any trace of the nodes which characterize that species.
The fauna of the upper half of the Cherry Valley limestone consists largely of cephalopods. These are confined to a few layers near the middle of the bed. Extraction along bedding planes is exceedingly difficult except under propitious conditions of weathering. In general three cephalopod horizons can be rec- ognized, each marked by a bedding surface, though occasionally the shells are packed so thickly and so deeply that the beds are
18 BULLETIN 109 18
not distinct. The lowest bed, and the poorest, usually contains only fragments of the characteristic Agoniatites vanuxemi. It has yielded some of the rarer and more interesting of the smaller forms, including Acleistoceras jonesi at Stockbridge, V erticoceras rectum at Stockbridge, Ovoceras oviforme at Stockbridge and Union Springs, and Michelinoceras swarthi.
The overlying bed appears to lack most of the rarer nautiloids, and consists largely of Agoniatites. Striacoceras typum (Sae- mann) is present. The highest bed contains the best preserved of the species of this orthoceracone, as well as the most abundant ones. Agoniatites still persists, though it is not uncommon to open large slabs at this layer without exposing a single specimen of this form, This bed has yielded all of the gyroceracones which I have collected, as well as Centroceras marcellense and the large brevicones. The absence of Agoniatites in this layer is charac- teristic of the Stockbridge locality, but is less marked at Union Springs and at Manlius is nonexistent. It is this layer which is exhibited in the New York State Museum bearing numerous am- monoids, orthoceracones, and two specimens of the rare large brevicones of the Cherry Valley. (See Miller 1938, frontispiece. )
With these horizon markers in mind, it is possible to turn to the type section of the Cherry Valley limestone and by recogniz- ing the same layers, to determine the point in the section which is represented farther west as the lithological base of the Cherry Valley limestone. Clarke (1901, p. 121) records 328 feet 2 inches of shale below the appearance of limestone in the section. The next measured interval, of 1 foot 5 inches consists of a series of lime- stones separated by shale beds, of which the lowest carries lV ern- eroceras, Vhe overlying shale, 4 feet 9 inches is noted for an abundance of Agoniatites nodiferis (Hall). Above this I have found the section to differ from that of Clarke, and find it possible to recognize the two main divisions of the Cherry Vialley proper, the lower containing Proetus, Aulopora, but only rare and frag- mentary cephalopods, the upper bearing the cephalopod layers, in which Agoniatites is more abundant at the base and Striacoceras at the top. The remainder of the section can be ignored. The over- lying shales belong to the Chittenango member. When followed up- stream the crest of a low fold is encountered as a result of which
19 WERNEROCERAS IN NEw YorkK: FLOWER 19
this section is repeated down to the Agoniatites nodiferis bed at the base of the Cherry Valley. Reexamination of the section has shown that the writer was probably in error in correlating this bed with the middle shaly parting between the coral and cepha- lopod members of the Cherry Valley limestone in more western areas. (Flower, 1936.)
Werneroceras plebiforme (Hall) Plate 1, fig. 3
This species has been redescribed with complete bibliographic references by Miller (1938) and the present description is re- stricted to such supplementary and revisionary data as are sup- plied by our specimens. The largest and most complete indi- vidual consists of the internal mold of the outer whorl and a small portion of an inner whorl, and an impression of the exterior to which adhered numerous small fragments of the shell as well as a part of the internal mold of the earlier whorls. Most of the shell fragments and interior were so badly weathered that they could not be retained, and crumbled under cleaning. However, the external mold showed remarkably clear surface features, For purposes of illustration an artificial rubber cast was made from the external mold and applied to the natural internal mold of the outer portion of the conch.
The dise attains a maximum of 130 mm. in diameter. Por- tions of four whorls are preserved, and comparison with other specimens indicates that within the apparent umbilical gap of 1g mm. there were originally at least four additional volutions not indicated on the present individual. The section of the outer whorl is slightly distorted; apparently the arching of the ventral wall has been exaggerated by slight lateral flattening. In its present state the apertural end of the specimen shows a whorl height of 50 mm., and the width, which is much greater than the height even in the present compressed specimen, must have been at least 80 mm. The impressed zone has a depth of 20 mm.
The surface is marked by a pair of prominent lateral spines which are seen on typical internal molds only as nodes, The series of specimens from Cherry Valley fail to show the nodes on the lower part of the shell. Although in the mature whorls the spines tend to be somewhat more completely filled by shell material, exfoliation is largely responsible for the condition of
20 BuLLETIN 109 20
the figured specimens. The nodes shown on our specimen are stronger than was previously suspected, and increase rather than decrease in prominence on the later whorls. The nodes increase ‘n size on the last two volutions, but decrease in prominence. There are twelve on the next to the last volution, and only eight, not all of which are preserved, on the final whorl. The nodes of this whorl are preserved only basally, but even on the internal mold they projected markedly, and are broken just beyond their bases. The large size of the nodes, the last of which is 9 mm. ‘n width and 11 mm. in length, suggests that the spines of the surface may have approached in prominence the nodes of Herco- ceras Barrande. However, in Werneroceras the nodes are uni- formly solid projections, hollow only at the base, and have no relation to the spoutlike nodes of the Hercoceratide.
The lines of growth are very clearly shown in some of the inner whorls, though naturally only the lateral portion is shown. These consist of closely spaced striz and lire, generally fine and threadlike, but occasionally thickened at irregular intervals giv- ing the surface an obscurely fasciculate appearance. These lines slope apicad from dorsum to venter over the entire exposed sur- face. As often happens in nodose ammonoids, the lines of growth are modified where they come in contact with the spines. Apicad of each spine the lines of growth are more markedly oblique than elsewhere, and are relatively transverse after a node is passed.
Discussion—Comparison of th Stockbridge material with the types and with a fine suite of specimens in the New York State Museum from the type locality shows that while there is some variation within the species, there does not seem to be justifica- tion for dividing it. Variations noted have to do with the ratio of height to width of the whorl, and also with the closeness of coiling. In neither respect does the Stockbridge material differ from specimens from the type locality of the species. There variation is accompanied by so many specimens expressing in- termediate conditions between the extremes that the conclusion was reached that a single variable species is involved,
Type.—University of Cincinnati Museum, No. 22866, hypotype.
Occurrence.—From the ]Werneroceras zone at Stockbridge Falls, Oneida Creek, Madison County, New York. The syn-
21 GONIOCERAS FROM VIRGINIA: FLOWER 21
types, and all previously known representatives of the species are from Cox’s ravine, Cherry Valley, New York.
REFERENCES
Clarke, J. M. 1901. Marcellus limestones of central and western New York and their faunas. New York State Mus., Bull. 49, pp. 115-138. Flower, R. H. 1930. Cherry Valley cephalopods. Bull. Amer. Paleont., vol. 22, No. 76, pp. 9 pls. Hall, J. 1879. Paleontology of New York, vol. 5, pt. 2. Miller, A. K. 1938. Devonian ammonoids of America. Geol. Soc. Amer., Special papers, No. 14, 255 pp., 39 pls.
Hr A GONIOGCERAS PROM VIRGINIA
ABSTRACT
A new species of Gonioceras from Virginia represented by an exception- ally large specimen is deseribed and figured. Comparison with other Gonioceras indicates that while knowledge of that genus is unsatisfactory, the beds yielding the specimen are regarded as probably lower Trenton in age.
INTRODUCTION
A large Gonioceras in the collections of the University of Cin- cinnati Museum is remarkable both for its unusual size and for its affinities. The specimen is exceeded in size by only one other known to the writer, a specimen figured by Troedsson (1926, pl. 65) of Gontoceras groenlandicum Troedsson, of the Cape Cal- houn series of northern Greenland. Further, the species is closely related only to Gonioceras holtedahli Vroedsson of the Gonioceras Bay limestone of northern Greenland. There is some question as to the exact age of the Gonioceras Bay limestone, Troedsson (1926) originally regarded it as Black River in age, but Teichert (1937, pp. 14-18,) has shown that it is probably best regarded as lower Trenton in age. The Chickamauga limestone has generally been recognized as containing several distinct hori- zons, but has been considered to be older than Trenton, and has been referred to the Blount group, believed to be intermediate in age between the Chazyan and the Black River,
22 BuLLetTiIn 109 22
DISTRIBUTION OF GONIOCERAS IN AMERICA
Gonioceras first appears in the Chazyan of the Champlain Val- ley, where it represented by G. chaziense Ruedemann (1906) in the Crown Point limestone, middle Chazyan. The writer has subsequently found a different but related species in the upper Chazy Valcour limestone of the same region. Practically con- temporaneous with these occurrences in the north, is the appear- ance of Gonioceras in the lowermost Ordovician strata exposed in the Nashville dome. An as yet undescribed Gomioceras ap- pears in the Murfreesboro limestone, a species which appears to be closely allied to the Chazy species of the Champlain Valley. The overlying Pierce limestone is a bryozoan facies which has not yielded cephalopods, but Gontoceras reappears in the next formation, the Ridley limestone, where it was identified by Gallo- way (1919) as G. anceps Hall. It is very doubtful whether it is actually conspecific with the Black River species of New York, which is not only widely separated geographically, but consider- ably younger. Precise correlation of the Lower Ordovician of the Nashville Basin with the Chazyan of New York is not very certain, The Murfreesboro limestone contains in addition to the Gontoceras, Ruedemannoceras stonense (Safford, 1860, p. 290, pl. 4, fig. 2) and a Centrocyrtoceras. Ruedemannoceras and Gonioceras occur together in both the Crown Point and Valcour limestones of the Champlain Valley. FR. stonense is the only known occurrence of that genus in any region other than that in New York. Centrocyrtoceras is known in the Champlain Valley from only one small undescribed species from the Val- cour limestone. The Murfreesboro limestone may on_ this basis be regarded as equivalent to the middle or upper Chazyan, the Centrocyrtoceras apparently favoring the latter correlation. However, middle Chazyan cephalopods are not very abundant in the Champlain basin, and are probably not completely known.
The Pamelia limestone of western New York occasionally yields Gonioceras, though the species has not yet been studied closely. This formation was at one time regarded as Chazyan,
bo co
23 GoNIOCERAS FROM VIRGINIA: FLOWER
then placed in the Stones River group, and has more recently been regarded as basal Black River, though on the basis of the presence of the thinning edge of the formation overlapping strata regarded as Chazyan in the Ottawa Valley, and it does not seem that the evidence thus far presented necessitates or justifies this change, proposed by Wilson and later accepted by Kay.
Gonioceras is abundant in the Watertown limestone of the Black River group in western New York, but is unknown in the Black River of the Champlain Valley. The Watertown species is Gonioceras anceps, but restudy will probably show that more than one species is actually present, as specimens of comparable width show marked variation in the rate of expansion. Gomioceras occidentale Hall and G. occidentale var. homerense Foerste char- acterize the Platteville of Black River age in Wisconsin. G. kayt Foerste was described from the Trenton Decorah formation. Foerste (1932-33) later recognized both G. occidentale and G. kayi from the Platteville member at Mineral Point, Wisconsin. G. occidentale has been found by the writer in beds of probably Platteville age in the cryptovolcanic structure of Kentland, In- diana.
In southern Ontario Kay (1937, pl. 9) has found an unde- scribed Gonioceras to be characteristic of the Rockland forma- tion, basal Trenton. Kay also includes in the Rockland the lime- stones of the Paquette Rapids which contain a Gonioceras close to G. occidentale. These beds have been formerly regarded as Black River in age, but-Kay regards them (1942, p. 604) of higher Rockland age, though the basis for this conclusion is not made clear. These beds carry a distinctive fauna, including many species absent from the typical Rockland, and also a few species, notably Receptaculites occidentalis Salter and Macleurina logani (Salter) which were originally described from these beds, and which Kay (1937) regards as diagnostic of the Rockland. Available sections illustrate that the Paquette Rapids fauna occurs above massive beds bearing -Alctinoceras which appear to be the equivalent of the Watertown member of the Black River. How- ever, the possibility that the fauna may be older than Rockland has not received adequate consideration as yet. Certainly its oc- currence above the Watertown member of the Black River is not adequate proof of its Trenton age.
24 BuLLeTIN 109 24
While it is not possible to discuss the intricacies of correla- tion and nomenclature of the Ordovician of Ontario at the pres- ent time, it should be pointed out that the Trenton age of the Paquette Rapids beds was stated categorically by Kay but not proved, Further, the present boundary between the Black River and the Trenton is not a natural one. Kay has arbitrarily se- lected the top of the Chaumont formation, which includes the Leray and Watertown members where they cannot be differen- tiated, as the top of the Black River, and has arbitrarily used the strata regarded in Ottawa as Trenton as the type section of that formation. The “Trenton” beds which contain Gonioceras in southern Ontario are Rockland in age. They are absent in the type section of the Trenton at Trenton Falls, and likewise in the type section of the Black River. As such, they are intermediate in age, and only close faunal study can determine in which group they should be placed.
The remaining important occurrence of Gonioceras is that of northwestern Greenland. G. holtedahli Troedsson occurs in the Gonioceras Bay formation which Troedsson (1926) originally regarded as Black River in age, largely because he saw in the overlying Cape Calhoun formation fossils of Black River affini- ties, and felt that that formation might embrace the Black River in part also. Teichert (1937) has subsequently reviewed the problem of the age of these beds, and came to the conclusion that they were probably not older than basal Trenton, apparently ac- cepting the Rockland as Trenton. The overlying Cape Calhoun beds contain Gonioceras wullfi Troedsson, G. groenlandicum Troedsson, G. angulatum Troedsson, and G.cf. groenlandicum, Troedsson believed that these beds may range from Black River to Richmond. Teichert (1937) also regards the Cape Calhoun as probably comprising several distinct horizons. The forma- tion is thick, and it was not possible to collect the fossils with regard to their stratigraphic relationship. Teichert (1937) re- gards the formation as Trenton, at least in part. S. K. Roy (1941) refers the Cape Calhoun to the Richmond without ques- tion, but treats the Red River series of Manitoba in the same
bo Or
GONIOCERAS FROM VIRGINIA: FLOWER 25
summary fashion, and, even more surprisingly, regards the Viola limestone of Oklahoma as Richmond, considering the presence of a species from Mt. Silliman related to Il’estonoceras deckeri of the Viiola limestone as evidence of Richmond age. Teichert points out that of the Cape Calhoun cephalopods, only three genera are not known to occur in strata of pre-Richmond age. These are Apsidoceras, Huronia and Danoceras. The writer has recently found Apsidoceras among upper Trenton material from Montreal.
From the above summary it is evident that Gonioceras has a very considerable vertical range. In the Champlain Valley it is confined to the Chazyan, and is not known from the Black River. In the Tennessee Basin it occurs in the Chazyan Murfreesboro and again in the Black River Ridley limestone. Though generally regarded as an arctic genus, the earliest Gonioceras are not boreal, at least in their known distribution. It is significant that the genus has not been found in the Chazyan of the Mingan Islands, former- ly regarded as very closely allied to the New York.Chazyan, Re- study of the Champlain cephalopods shows that while a strong resemblance remains, practically none of the cephalopod species of New York and the Mingan Islands are identical, and there is more in common between the Murfreesboro fauna and the Chaz- yan than the present published data would indicate, suggesting a dominance of austral over true boreal elements in the faunas of the type Chazyan.
In Black River time Gonioceras is an essential component of the faunas which have been regarded as boreal. The Black River fauna continues on into strata now regarded as lower Trenton with specific changes, but without any major appearance of new genera or the disappearance of old ones. Possibly the Cape Calhoun formation may contain the youngest of the known spe- cies of Gonioceras, but it is not certain that even these strata are younger than lower Trenton. However, in this region there may reasonably be expected to be preserved faunas of Black- River and Richmond affinities, for it is generally known that in Trenton time the Black River fauna disappeared from eastern North America, retreating northward, where it developed gradu-
26 BULLETIN 109 26
ally into the Richmond fauna. Formerly it was thought that the nyarteal fauna did not invade eastern North America again until Richmond time, but Kay (1935) has clearly demonstrated the presence of this fauna in the upper Trenton of Minnesota, New York and Ontario,
Gonioceras hubbardi is clearly not related closely to any of the Chazyan species, and the condition of its sutures suggests only Gonioceras holtedahli Troedsson of the Gonioceras Bay lime- stone. It appears safe to conclude that the stratum which yielded the specimen is probably to be correlated with that formation, but this is not very satisfactory, since the age of the Gonioceras Bay limestone is not established upon a very firm basis. Further, two other unsettled problems make the matter very uncertain. First, it has not been demonstrated that species of Gonioceras evolve in any orthogenetic series in strict accordance to the oc- currence of the species in the stratigraphic column. Second, it is by no means certain where the best place may be to draw a boun- dary between the Black River and the Trenton. The Cape Cal- houn species of Gonioceras and also G. cf. groenlandicum of the Rockland of Ontario, seem to have the lateral portion of the su- tures more strongly recurved than any Black River species, or than G. hubbardi or G. holtedahli. However, as seen from the above summary, much still remains to be learned about Gonio- ceras in Aimericz “ty Gonioceras hubbardi Flower, n. sp. Plate 3, fig. 7
The holotype is a natural horizontal section consisting only of the phragmocone, 370 mm. in length. At the adoral end one side is embedded in the rock and not exposed; the other side at the opposite end is lost by weathering, as the plane of weather- ing is irregular, and slightly oblique to the plane of the specimen. The rate of lateral expansion is moderate, much less than is con- sidered normal for the genus. The conch expands from 98 mm. to 100 mm. in a length of too mm. in the middle portion. Al- though the sides are not clearly exposed adorally, the condition of the sutures suggests that the same expansion Gonrinnee to the adoral end of the specimen.
The section of the conch is not clearly shown, but cert
ae! ; ain of Its features can be inferred from the holotype and
also from the
ee Se
27 GONIOCERAS FROM VIRGINIA: FLOWER PATE
paratype. Adapically the siphuncle clearly lies very close to the lower wall of the shell, which is apparently very slightly con- vex. The other wall is apparently more strongly arched. Near the middle of the specimen practically the entire width of the shell is preserved at a region slightly dorsad of the siphuncle.
The sutures must be nearly straight vertically, though strong- ly curved laterally, showing the pattern typical of the genus. The details of the lobation of the suture vary slightly from dorsum to venter, presenting variations in different parts of the shell which compare with differences which have been used elsewhere for specific criteria in Gonioceras. The mid-ventral lobe of the su- ture is more transverse at the center than is the mid-dorsal lobe.
The siphuncle which lies close to the ventral wall, appears to be quite typical of the genus in the form of the segments. At the base of the specimen a segment expands from 8 mm. to 18 mm. and is 2.6 mm. in length. The vertical dimensions of the seg- ment have not been determined, but as in most Gonioceras, the width is probably considerably greater than the height.
At the adoral end of the specimen the camer appear to have become slightly crowded, but no trace of the living chamber re- mains. There is no evidence of the fusiform outline shown in the mature portion of Gonioceras groenlandicum Troedsson. At the base, the specimen appears to be expanding at the same slow rate as the central portion. The adoral end may be contracted very slightly, but the present evidence fails to show this conclusively.
The sutures are closer to those of Gonioceras holtedahli Troedsson than to any other described species. They are shown clearly in the accompanying illustration.
Discussion.—The slender form is perhaps the most salient feature of this species. Comparison with previously described species of Gonioceras serves for the most part to show that they have been inadequately described and figured. The Chazyan species, G. chaziense, is not only smaller, but also has pro- portionately broader lateral zones, though the sutures do not ex- tend so far apicad at their lateral extremities. The same differ- ences serve to distinguish this from an undescribed Valcour lime- stone species, The Murfreesboro form is known to me_ only
28 BULLETIN 109 28
from incomplete specimens, not showing the lateral portion of the conch clearly. However, there is good indication that this form agrees in general with the Chazyan types in not having the sutures very strongly recurved, and also is peculiar in that the height is larger in proportion to the width than in any other spe- cies.
The suture pattern is closer to that of Gonioceras holdedahli Troedsson (1926, p. 83, pl. 48, figs. 1-2; pl. 49, fig. 1; pl. 50, fig. 1) than to any other known species. The lateral saddles of the suture are rounded, and the suture becomes straighter though oblique, on approaching the lateral margin, In G. wulffi the sutures are more broadly rounded laterally, and do not become straight near the edge of the conch. In G. angulatum and G. kayi the lateral saddles are more angular, the sutures straighter in the lateral zone. In G. groenlandicum the sutures extend much farther apicad laterally than in this species, and remain more curved as in G. wulffi. In G. anceps and G. occidentale the conch expands more rapidly. Typical G. anceps does not have the sutures so strongly recurved laterally. Our species is distinguished from G. holtedahli, seemingly its closest relative, in that the lateral flanges of the sutures do not extend so far apicad. The type shows this clearly, owing to the mode of preparation. The natural section showed a little relief, and to bring out the precise course of the sutures it was necessary to black in every other camera. In this way the distinction of the sutures is retained, even where they come very close together, a phenomenon which makes the tracing of sutures in strongly lobed species of Gonioceras sometimes very difficult.
Types.—Holotype and paratype, University of Cincinnati Mus- eum, Nos. 22846-7.
Occurrence.—From the Chickamauga limestone, north side of Buckeye Mt., Giles County, Virginia. The section has been given by Hubbard and Croneis (1924).
ioe tun i
29 GONIOCERAS FROM VIRGINIA: FLOWER 29
REFERENCES
Foerste, A. F.
1930. Three studies of cephalopods: Il. Ordovician cephalopods of the north central states. Denison Univ. Bull., Sei. Lab., Jour., vol. 24, pp. 268-381, pls. 41-63.
1932-33. Black River and other cephalopods from Minnesota, Wisconsin, Michigan and Ontario. Part I, Denison Univ. Bull., Sei. Lab., Jour., vol. 27, pp. 47-136, pls. 7-37. Part II. Ibid., vol. 28, pp. 1-146.
Galloway, J. J.
1919. Geology and natural resources of Rutheford County, Tennessee. Tennessee Geol. Surv., Bull. 22, 81 pp., map.
Hubbard, G. D. and Croneis, C.
1924. Notes on the geology of Giles County, Virginia. Denison Univ. Bull., Sci. Lab., Jour., vol. 20, pp. 307-377, pl. 43.
Kay, G. 'M. ‘ 1935. Ordovician Stewartville-Dubuque problems. Jour. Geol., vol. 43, pp. 561-590, 10 figs.
1937. Stratigraphy of the Trenton group. Geol. Soc. Amer., Bull., vol. 48, pp. 233-302, 10 pls., 13 figs.
1942. Ottawa-Bonnechere graben and Lake Ontario homoctine. Geol. Soc. Amer., Bull., vol. 52, pp. 585-646, 7 pls., 7 figs.
Roy, S. K.
1941. The Upper Ordovician fauna of Frobisher Bay, Baffin Land. Field Museum of Nat. Hist., Geol. Mem., vol. 2, 212 pp., 146 figs.
Ruedemann, R. 1906. Cephalopoda of the Champlain Basin. New York State Mus., Bull. 90, 611 pp., 38 pls., 57 figs.
Safford, J. M. 1869. Geology of Tennessee. Nashville, 550 pp., 7 pls.
Teichert, C.
1937. A new Ordovician fauna from Washington Land, North Green- land. Meddelelser om Gronland, Bd. 119, nr. 1, pp. 1-65, pls. 1-7.
Troedsson, G.
1926. On the Middle and Upper Ordovician faunas of northern Green- land, I, Cephalopods. Meddelelser om Gronland, Bd. 71, pp. 1-157, pls. 1-65,
30 BULLETIN 109 30
IV. INVESTIGATIONS OF ACTINOSIPHONATE CEPHALOPODS
ABSTRACT
‘
Previous treatment and investigations of actinosiphonate cephalopods are briefly reviewed. Evidence is offered to show cases in which actinosti- phonate structure has appeared independantly in several distinct genetic lines, ancl’ more cases are suspected of having undergone similar develop- ment. As a structure of polyphyletic origin, actinosiphonate structure is too broad a generalization to have any genetic significance. However, various types of actinosiphonate structure occur, larly Ordovician cephal- opods, Valcouroceras and Minganoceras show some distinctive structural features and ontogenetic anomalies. Actinomorpha is described as an ex- ample of bipectinate rays of deposits in the Ordovician. The deposits of Archiacoceras ave described in detail on the basis of serial sections. Those of the Brevieoceratide are briefly described.
INTRODUCTION
Actinosiphonate deposits within the siphuncles of cephalopods are differentiated from annulosiphonate deposits by the develop- ment of numerous processes extending from a thin lining of the siphuncle radially toward the center. Such structure was taken by Hyatt (1900) as the criterion of one of the two divisions which he made in the Cyrtochoanites. In the Actinosiphonata, as opposed to the Annulosiphonata, were placed, in addition to genera known to possess actinosiphonate deposits, practically all brevicomic shells such as were once placed in the too-inclusive genus Gom- phoceras. Foerste (19206) reinvestigated the Actinosiphonata and pointed out for the first time the perplexing problem of the peculiar and seemingly erratic distribution of actinosiphonate structure. Not all of the genera formerly placed in the Actinosi- phorgta were actinosiphonate. In fact, a very considerable group of genera appear to be completely devoid of such deposits. Hyatt had recognized that actinosiphonate structure did not hold throughout his Actinosiphonata, while not all of the Annulosi- phonata were annulosiphonate. He believed that each type of structure was developed in its own group. Annulosiphonate cephalopods have been treated by various recent investigators, and at least two types of structure are involved, to which Strand (1934,) applied the names of lunettes, for the deposits of actino-
Bil ACTINOSIPHONATE CEPHALOPODS: FLOWER 31
ceroids, and bulettes for the deposits of other forms. The bul- ettes he regarded as derived from the connecting ring, and prob- ably rather closely related to actinosiphonate deposits. Flower (1942) has proposed that the annulosiphonate deposits of the actinoceroids may be also derived from the connecting ring, though indirectly by growth of a part of the ring which was spe- cialized first into an eyelet (Flower, 1942) and which was pre- sumably nonporous.
Among the simpler genera assigned to the Actinosiphonata are the Oncoceratidee, which lack all trace of actinosiphonate structure. Attempting the removal of such forms from the group, Teichert (1933) proposed to substitute the name Cyrtoceroidea, and later (1939) presented a classification of the known actino- siphonate genera into families which were based largely upon the form of the shell. The scheme which he proposed is a logical and a convenient one, but it is to be greatly feared that it is not natural. The present evidence suggests strongly that actinosi- phonate structure developed several times independantly in dif- ferent lines of descent within the Nautiloidea. Further, addition- al studies have lead to the belief that true genetic relationships can be traced among various genera, and that such relationships show little constancy in the form of the shell, upon which Teich- ert has based his familous divisions,
Actinosiphonate structure is not as yet known from any cepha- lopods older than the Chazyan. There two genera occur, Min- ganoceras Foerste and Valcouroceras Flower, n. gen. Diestoceras has also been reported from the Chazyan of the Mingan Islands, (Foerste, 1938) but it is not certain that this is a true Diestoceras, and the single Chazyan species is not known to have actinosi- phonate structure. Valcouroceras gives rise to those Upper Ordovician cephalopods which are currently assigned to MVether- byoceras Foerste,* and is very closely related to species which
*
Unfortunately Wetherbyoceras is based upon Cyrtoceras conoidale Wetherby of the Cincinnatian. That species cannot be recognized unless the original type is found. According to Foerste, (in correspondance) types of this and other Cincinnatian eyrtoceracones have been lost. Under the circumstances, it will not be possible to recognize Wetherbyoceras Foerste,
32 BULLETIN 109 32
have been described and figured in connection with this generic name. It is not certain that Diestoceras is closely allied to this stock, nor is it certain which if any of the Silurian and De- vonian actinosiphonate cephalopods may be traceable to this early beginnine of the Actinosiphonata proper.
However, in tracing the development of Oncoceras and Oono- ceras, (Flower, 1942, p. 24, fig. I, p. 30) it appears that in the Silurian Oonoceras attains a second period of form modification resulting in new generic types. One of these is Oocerina Foerste which can be separated from Oonoceras only by the development of actinosiphonate deposits. In all other differences, which in- volve the surface markings and the width and expansion of the segments of the siphuncle, these two genera intergrade. From this it is necessary to infer either a degree of convergence in con- temporaneous species almost too remarkable to be credited, or that Oocerina is nothing more than an Oonoceras which devel- oped actinosiphonate deposits.
A second and even more startling case of the development of actinosiphonate deposits is encountered in another line of descent probably traceable to the Oonoceratide. In cyrtoceracones of the Silurian probably best placed in Cyrtorizoceras, increase in coiling resulted in the development of a low-spired trochoceroid. This 1s Oxygonioceras Foerste. A considerable number of spe- cies from the Middle Silurian of Bohemia described by Barrande suggest this relationship because they are so nearly intermediate between the two genera that there is some doubt in which they are best placed. Oaygonioceras in turn seems to be the ancestor of Mitroceras and Foersteoceras of the Upper Silurian, in which actinosiphonate deposits appear. These genera form the first of the Brevicoceratidae, which in Middle Devonian time developed into degenerate loosely coiled trochoceroids, two distinct gyroceraconic genera which appear to have developed indepen- dently from trochoceroid ancestors, and a variety of breviconic genera. This family, treated in more detail in a work bv the writer on Middle Devonian cephalopods of New York to be pub- lished by the New York State Museum, shows not only a third
line of actinosiphonate cephalopods which cannot be placed with
33 ACTINOSIPHONATE CEPHALOPODS: FLOWER sie)
either of the first two as a genetic group characterized by actinosi- phonate deposits, but also two other features of interest. First, the actinosiphonate deposits within this family are highly dis- tinctive in form, and show that actinosiphonate structure is too broad a generalization. There are various types of actinosiphon- ate structure, and one type is highly characteristic of this family. Perhaps further study of other actinosiphonate cephalopods will yield morphological features by which other independent groups characterized by such structure can be recognized, Second, this family shows that not only can actinosiphonate structure appear in a line in which such structure was originally absent, but that it can give rise to new forms in which the structure may be lost. This was shown strikingly by the breviconic genera. Brevico- ceras Flower, (1938,) which is typically actinosiphonate, may give rise to Exocyrtoceras and Verticoceras, also possibly Ovo- ceras, in which the structure is never developed. This is shown by the fact that the genera are so closely allied in all other fea- tures, that it is necessary to set arbitrary limits for their separa- tion. If the presence or absence of actinosiphonate structure were used, some species placed in Brevicoceras on the basis of section and sutures and the hyponomic sinus would have to be removed to Exocyrtoceras. Still another division of species be- tween these two genera would be effected if the sutures were considered diagnostic, and still another if the presence or ab- sence of the hyponomic sinus is used. As this last character has the dubious sanction of long usage, and seemed to be no worse at least than the others, it was retained as the diagnostic feature, species with a sinus being placed in Brevicoceras, while those without it were placed in Evocyrtoceras. In the Brevicoceratidae relationship was largely based upon the presence of species which bridged the gap between genera erected on the customary basis of shape, section, sutures, and which, except for the ultimate logs of actinosiphonate deposits, appear to be quite uniform in the structure of the siphuncle. It is largely upon the strength of this family, which contains brevicones, trochoceroids and eyro- ceracones, that it has seemed necessary to reject Teichert’s fam- ilies based upon the form of the shell.
34 BuLLETIN 109 34
There are other cases which it has not been possible to inves- tigate adequately in which actinosiphonate structure may have appeared in other lines of descent. One of the most striking is found in the phragmoceroids. Two Silurian genera, Phragmo- ceras and Conradoceras lack actinosiphonate deposits. In the Middle Devonian of Rohemia they are replaced by two actinosi- phonate genera, Bolloceras and Paraconradoceras ( Foerste, 1926). Indeed, Foerste placed some Devonian species in Phrag- moceras but these differed from all known Silurian species in be- ing actinosiphonate. Further, the features of the aperture upon the basis of which Foerste placed these species in Phragmoceras, and placed others associated with them in Bolloceras, did not ap- pear to be constant, (Flower, 1938, p. 61-63) therefore the writer proposed that the better division between these genera would be the presence or absence of actinosiphonate structure, thereby placing all Devonian species formerly included in Phragmoceras, in Bolloceras. The Silurian Phragmoceras and Conradoceras are stratigraphically isolated from the Middle Devonian Bolloceras and Paraconradoceras, From what has been learned of homeo- morphy in other fossil groups, it may be that the Silurian and Devonian forms represent merely a remarkable case of form convergence, and that they are not closely related at all. How- ever, there is still the possibility that Bolloceras and Paraconrado- ceras may represent yet another case of development of actinosi- phonate structure within distinct lines of descent. Certainly no other origin for these genera has yet been suggested.
Another problem, which was first noted by Foerste (1926 ) was the apparent erratic distribution of actinosiphonate deposits. Sometimes they did not appear in all members of a group which seemed to be a good genus on the basis of all other features. Sometimes Foerste used actinosiphonate structure to divide such form-genera, as in the separation of Oocerina from Oonoceras.*
This remains at present as the only good difference. Foerste used in addition the presence of annuli on Oocerina, but the transverse ridges of the surface are not true annuli (Flower 1942, p. 24-31) and Bohemian species show a gradation between the ridged surface of the genotype of Oocerina and typical Oonoceras.
35 ACTINOSIPHONATE CEPHALOPODS: FLOWER
jot) or
However in cases where no other support could be found for separating extant genera, division on the basis of actinosiphonate structure was not attempted. Amphicyrtoceras for example, is not known to be actinosiphonate in the genotype, but Foerste referred to it Amphicyrtoceras ? penultimum Barrande which is actinosiphonate but it is otherwise typical of the genus. Other examples are cited by Foerste (1926, p. 298) who also called attention to the fact that nothing was known of the constancy of actinosiphonate structure within a species. In some, as in IV’eth- erbyoceras, it appears to be uniformly present. In some other species, it is shown in some individuals but not in others. Teich- ert (1939, 1940) proposed that conditions of preservation might account for this difference. This may and almost certainly does apply to many cases, but there are examples known in which the preservation of all other features is excellent, and there seems to be no good reason why actinosiphonate deposits, if originally present, should not be retained. Flower (1938, p. 8-10, 1939, p. 63-66) suggested that actinosiphonate deposits might be structures which appeared late in the life of the organism, prob- ably gerontic. The two explanations are not mutually exclusive. e
SPVUCIURE OF ACTINOSIPHONATE DEPOSITS
In general those deposits which have been classed as actinosi- phonate apparently begin as a thin organic lining within the siphuncle. From this lining processes develop which converge toward the center of the shell. Sometimes these are essentially tabular, and may pass from one segment to the next without any apparent break. In tracing the individual rays from segment to segment, they are normally obscured at the septal foramen, but in many cases pass it unmodified. As the rays of deposits are traced orad through a series of camerze they may increase in number. This may be the result of either the appearance of new rays between older ones, or the division of any of the rays. Striz on shells behave similarly.
Rays of actinosiphonate deposits may be simple lobes, or they may be complexly divided, usually alternately and somewhat ir-
36 BULLETIN 109 36
regularly bipectinate, as noted in Actinomor pha, described below, and as also shown by Teichert (1940) in Danoceras. Both simple and bipectinate rays are known from the Ordovician through the Devonian. The published information is completely inadequate at the present time to show whether such differences are constant within a genus, as seems very probable, and if so, what types characterize the known actinosiphonate genera.
In some cephalopods continuous rays are not formed, but from the thickening of the siphuncle lining at the septal foramen ina manner sometimes recalling I!’estonoceras which is not properly actinosiphonate, more or less regular ray like processes may ex- tend not only centrad toward the axis of the siphuncle, but also orad and apicad into the expanded part of the segments. Such deposits are quite distinct from those which form a continuous lining. They are characteristic of the genus Diestoceras of the Ordovician, and are known in the Devonian only in the family Brevicoceratide. No Silurian examples of this type of structure have yet been encountered.
Actinosiphonate deposits are in one instance clearly a modifi- cation of the connecting ring. Thin sections of Archiacoceras under most favorable conditions of preservation show no differ- entiation of the deposit from the original connecting ring. They agree with the connecting ring in conditions of replacement and texture, and differ in both from the true shell structures of the septal necks. Opaque sections suggest strongly that the same applies to the other genera which have been studied here, Val- couroceras, Actinomorpha, Herkimeroceras, as well as to Middle Devonian brevicones from the Eifel region too incomplete for certain generic diagnosis.
Probably the most peculiar feature of actinosiphonate struc- ture is its frequent absence in early portions of the siphuncle. Re- capitulatory significance of such a phenomenon seems dubious, for if any ontogenetic progression is to be found in such parts, which can be altered by further secretion, the most advanced con- dition would be expected in the older part of the shell. be that other factors, possibly mechanical, are involved.
As has been noted above, actinosiphonate structure is a gener-
It may
aie ACTINOSIPHONATE CEPHALOPODS: FLOWER 37
alization, rather too broad, to cover a variety of superficially sim- ilar structures which seem to have appeared several times in the history of cephalopods independently. [*urther statements con- cerning the morphology of these deposits are best confined to the individual types studied.
CHAZYAN ACTINOSIPHONATE CEPHALOPODS
The oldest actinosiphonate cephalopods thus far recognized are Chazyan in age. They fall into two genera, probably closely re- lated, Minganoceras Foerste and Valcouroceras, Flower, n. gen. Minganoceras is known only from the genotype, M. swbturbina- tum from bed As5 of the Mingan formation of the Mingan Islands, and the species is apparently upper Chazyan, to be correlated with the Valcour limestone of the Champlain Valley. Appar- ently this species is known only from the holotype. The genus is depressed in section and faintly curved exogastrically, and is rather generalized in form. The sutures are essentially straight and transverse, the shell is not contracted at the aperture. Foerste (1938, p. 104, pl. 24, figs. 1-4) has supplied a very adequate de- scription and illustration of this species and genus. [alcouro- ceras is best developed in the Valcour limestone of the Champlain Valley, but is also known from the lower Chazyan. The Val- cour limestone material is fortunately abundant, though too often fragmentary, and usually preserves the internal structure clearly. It is exclusively from this genus that the following observations have been drawn. There is, however, no reason to believe that the siphuncular structure of Minganoceras is not similar in all essential features.
Valcouroceras is represented in the upper Chazyan by a con- siderable number of species. These differ from Minganoceras in form. The section is compressed in the early stages, the ven- ter narrowly rounded so that the section is subtriangular. In later stages the shell may become broader than high. Over the living chamber the shell is slightly inflated and contracts toward the aperture. Usually the venter loses its narrowly rounded con- dition here and the shell as a consequence loses its subtriangular aspect.
38 BULLETIN 109 38
Within the series of contemporaneous upper Chazyan species which make up the genus Valcowroceras as established on the basis of form and section, there exists an almost bewildering vari- ation of internal structure, having to do with the form of the seg- ments of the siphuncle and also with the actinosiphonate deposits within the siphuncle. However, further examination of this genus in the light of associated forms has made possible an explanation of some of these variations.
Form of siphuncular segments.—It has been previously noted by the writer (1941, p. 524-5) that the Chazyan cephalopods do not appear amenable to the usual division into orthochoanitic and cyrtochoanitic cephalopods. Instead, five groups were pro- posed for (1) orthochoanitic tubular siphuncles (2) subortho- choanitic siphuncles (3) cyrtochoanitic siphuncles which are suborthochoanitic in early stages (4) siphuncles which are cyrtochoanitic in the early stages later becoming suborthochoani- tic, and (5) siphuncles which are broadly cyrtochoanitic through- out. Valcouroceras clearly belongs in the third of these groups. Early stages of the siphuncle are essentially tubular. Later stages show expansion of the siphuncle within the camere to an extent which can be roughly correlated with the growth stage. Some of the species are small, and these commonly fail to attain broad- ly expanded segments at all. Only in the larger species are very broad segments attained. It is apparent from this that those in- dividuals which underwent a longer period of development, and which were long lived, attained a more advanced condition than did their smaller and presumably shorter lived relatives. This correlation is not perfect. The smaller and more primitive spe- cies may, as one can readily see, also produce large species which may agree with them in internal structure, while dwarfing of some of the large species may give rise to small species in which the siphuncle attains an advanced stage of cyrtochoanitic de- velopment. We have no examples of the former, but several of the latter, one in the Chazyan, and others in the closely related lV etherbyoceras of the Upper Ordovician.
The explanation of the plasticity of the siphuncle is relatively
39 ACTINOSIPHONATE CEPHALOPODS: FLOWER 39
simple. It applies not only to Valcouroceras, but also to a greater or lesser degree to the Oncoceratide, Oncoceras, Beloitoceras and Richardsonoceras of the Chazyan, and also to Allumettoceras which, together with Tripteroceras and an undescribed genus, seem to constitute a natural family of straight depressed cyrto- choanitic shells with empty siphuncles. That Chazyan speci- mens show this phenomenon more strikingly than younger Ordo- vician cephalopods which have been studied is believed to be at- tributable to a combination of two factors: 1. Chazyan species are nearer in time to the development of cyrtochoanitic struc- ture. Consequently if, as appears likely, it developed tachygenet- ically, the suborthochoanitic stage should be more conspicuous in Chazyan species than in those of the Black River and Trenton. Ulrich and Foerste (1933) have remarked that there seems to be no good division between orthochoanitic and cyrtochoanitic structures in the Canadian, and presumably cyrtochoanitic struc- ture must have been developed in the interval between the Chaz- yan and the Canadian, except, of course, in the case of the Actino- ceroidea, which underwent a completely independent develop- ment. As a consequence it is to be expected that even in the upper Chazyan, cyrtochoanitic structure has not become thor- oughly established in genera and families which it characterizes in Middle Ordovician and later horizons. 2. Further, the apparent wide discrepancy between the Chazyan and the younger cyrto- choanitic cephalopods in this respect may be more apparent than real. It must be remembered that in most Black River and Tren- ton formations early stages are exceedingly rare, and internal structure is not usually well preserved. In the upper Chazyan, however, abundant early stages have been found which can be studied by means of sections.
The very earliest stages of Valcouroceras have been encoun- tered only in apical fragments which cannot be assigned to any of the several species with certainty. In fact, except for the broad dorsum, they are very difficult to distinguish from similar stages in Beloitoceras. The segments of the siphuncle have essentially straight septal necks, very short and often obscure, and the con- necting ring is suborthochoanitic. The next stage in expansion
40 BuLLETIN 109 40
results in segments which are still slender, but in which the sep- tal necks are recurved, and the siphuncle begins to show indica- tion of a scalariform condition in vertical section, although the connecting rings are still only slightly expanded within the camere (fig. 2A). The next stage (fig. 2B) shows an increase in the scalariform condition, the neck being straight on the ven- ter, recurved on the dorsum, and with the connecting ring broad- ly adnate at its adapical end on the venter but not on the dorsum.
Figure 2. Structure of actinosiphonate deposits. A. Harly segments
of siphuncle of Valcowroceras lacking deposits. B. Later stage, show- ing beginning of thickening of ring on dorsum. CC. Segments of adoral end of Valcouroceras bovinum. Actinosiphonate structure is not evident, and is only slightly developed in cross sections. D. Vertical section of
Valcouroceras cyclops in which three distinct types of calcification are shown. This cannot be seen in cross sections. Same specimen as is illus- trated by other sections in Plate 2, figs. 5-6. X denotes plane of section of
Plate 2, figure 5. EK. Cross section of typical Valcowroceras siphunele. Generalized after a series of sections of V. cyclops. F. Cross section
through septal foramen of Brevicoceras pompeyense Flower. G. Detail of cross section of siphuncle of Archiacoceras ventricosum, showing strue- ture of rays and layers of the siphuncle lning.
This figure shows on the dorsal side of the siphuncle an or- ganic lining which, as will be shown below, appears to develop
41 ACTINOSIPHONATE CEPHALOPODS: FLOWER 41
as a thickening of the connecting ring itself. The outline of the original connecting ring may be taken to be the outer or cameral surface of this deposit.
The next stages (fig. 2C-D) show progressive expansion of the segments of the siphuncle. The connecting rings become more recurved on the dorsum, the areaof adnation becomes more pronounced on the venter, and the connecting rings are more strongly curved. In both figures the outline of the connecting ring is complicated by the presence of actinosiphonate deposits. In the last figure, 1D, the connecting ring has apparently not only grown by the addition of material to its inner siphonal sur- face, but also by the addition of material to its outer or cameral surface. Yet such deposits, by their origin and texture are sim- ilar to the connecting ring and contrast sharply with the septa and other true shell structures. They are not properly cameral deposits, except in that they lie outside of the original boundary of the siphuncle. In origin they agree with the connecting ring and contrast strongly with the true cameral deposits which are secretions of a true mantle surface.
Actinosiphonate deposits —Well-developed actinosiphonate de- posits in Valcouroceras have been studied by serial sections, both cross and longitudinal sections being used. In cross section the siphuncle is compressed. The thick lining of the siphuncle is well shown, and cannot be distinguished from the original con- necting ring. From it rays project toward the center of the siphuncle. In a section which was essentially parallel to the plane of the septum, the lobes were thicker on the ventral than on the dorsal surface. Massive lobes flank a small pointed ven- tral process, and become less massive and also shorter as the dorsum is approached. On another specimen, the reverse was found to be true, and the explanation was found in the discrep- ancy between the plane of the section and the plane of the sep- tum. Wherever the ground section came closest to the septum the siphuncle tended to be narrower, and the lobes of the deposits tended to become reduced. However, the significant fact seemed to be the bilaterally symmetrical arrangement of the lobes of the deposit within the siphuncle. Two cross sections are figured
here, Plate 2, figure 5, and I late 3, figure 7.
49 BuLuLETIN 109 a
The appearance of longitudinal sections varies greatly depend- ing upon the level to which such sections are ground. Plate = ficure 4 shows one which has been ground parallel to the axis of the siphuncle attaining its center. Here a thin continuous lin- ing is seen which is thickened at the septal necks in such a way as to appear annulosiphonate. The same condition is shown in text figure 1C. Such a section resembles |l’estonoceras so strong- ly that cross sections of that genus were made to determine whether actinosiphonate structure was developed there. None was found.
A section not attaining the center will cut some of the rays of the actinosiphonate deposit. In such a section in Minganoceras (Foerste, 1938, pl. 24, fig. 5) the rays may be seen projecting orad into each segment from the region of the septal foramen, but not attaining continuity from segment to segment. How- ever, the same sort of section may be achieved in Valcouroceras by a section taken at the correct level, while a section nearer the wall of the siphuncle will show that these rays are essentially vertical partitions. They extend farther toward the center of the siphuncle at the adapical end of the segment than at the adoral end, but can be traced from segment to segment, though very short and poorly developed at the septal foramen when they are all but lost in the thickened siphuncle wall from which they arise. ‘This is shown by the two sections on Plate 2, figures 5, and 6, Figure 5 is a cross section taken at the apical end of a fragment of shell, showing the deposits of the siphuncle. The deposits are thicker on the dorsum than on the venter here be- cause the plane of the section cuts the middle of the siphuncle segment on the venter, but on the dorsum lies just apicad of the septal neck, where the siphuncle is greatly expanded. The posi- tion of this section is shown in figure 1D by the line x. In order to study the siphuncle further, this specimen was sectioned obliquely, the plane of section attaining the center of the siphuncle adorally, while it passed obliquely away from the center adapic- ally so as to preserve the entire cross section shown in Plate 2,
figure 5. In the middle of the three segments shown, rays simi-
lar to those of Minganoceras are seen: they do not appear to at-
43 ACTINOSIPHONATE CEPHALOPODS: FLOWER 43
tain the adoral end of any segment. However, a more eccentric section, shown in the next adapical camera, shows the rays ex- tending from one end of the segment to the other, and fused at each end with the lining of the siphuncle. When this same specimen was ground parallel to the axis of the siphuncle, a con- dition such as shown in figure 1D» was found. The most per- plexing phenomenon here is the apparent differentiation of struc- ture within the actinosiphonate deposits. This was not observed clearly in any cross section. It is probable that, instead of any real differentiation of layers in the original organic deposit, the structures are here complicated by areas of dark calcite, often difficult to distinguish from the real deposits, which do not repre- sent original calcareous structures, but which owe their dark color to substances from decayed tissues. It was not possible to make enough sections of the specimen from which this drawing was taken to trace out the structure in detail, or to be certain that actinosiphonate deposits have been properly differeniated from tissue remnants. Whether by tissue remnants or real or- ganic calcareous deposits, there is clearly here some addition of material on the outside of the original connecting ring as well as on the inside.
Differentiation of various parts of the deposit in Valcouroceras is highly problematical. The cross section of Plate 2, figure 5 shows the margin of the lobes of the deposit to be darker than the remaining part, and the cavity is filled with light calcite. However, other specimens have failed to show similar phenom- ena, suggesting that it may be adventitious.
Genus VALCOUROCERAS Flower, n. gen. Genotype.—V alcouroceras bovinum Flower, n. sp.
The shell is an exogastric cyrtocone which varies in section among species, and also among growth stages. The early part of the shell is compressed, with the venter more narrowly round- ed than the dorsum, so that the section may be subtriangular. At the base of the mature living chamber the height and width may become equal, and in later portions the sides converge orad so that the section assures a compressed condition again. On the
44 BuLLETIN 109 44
gibbous living chamber the venter is usually as broadly rounded as the dorsum.
The sutures may be straight and transverse in the young, but generally slope forward on the ventral side of the shell, form- ing rounded lateral lobes and broad rounded ventral saddles. The siphuncle is close to the ventral wall, and varies in ontogeny from suborthochoanitic to broadly cyrtochoanitic.
The surface of the shell bears coarse rather distant transverse markings. No hyponomic sinus is developed.
The siphuncle has already been described in some detail for this genus. The outline of the segments is variable, and actino- siphonate structure is only well developed in later portions of the phragmocones of larger individuals.
Discussion.—This genus is erected upon the basis of a consid- erable suite of specimens representing various species from the Valcour limestone of the Chazyan. While it is evident that more species are represented among our material than are described at present, some are represented by material too fragmentary to jus- tify the application of new names. Unfortunately among such specimens are included the fragments representing the largest of all the species, which has supplied the best examples of actino- siphonate structure here. Such species of this sort as I have had occasion to figure, are designated simply as Valcouroceras, Sp.
The genus, although an exceedingly plastic one, does not lend itself to further division, largely because the known species fail to fall naturally into smaller and more restricted groups.
Valcouroceras differs from its contemporary, Minganoceras, in the more compressed section, more rapid expansion, and the gib- bous living chamber, as well as in the more subtriangular section of the shell. Outside of the Valcour limestone only one other species is known to the writer, an undescribed one from the Platteville limestone. Wetherbyoceras has been applied to Up- per Ordovician cephalopods which are closely related to Val- couroceras. They represent more advanced types, in that actino- siphonate deposits appear in earlier stages of the shell, and differ
45 ACTINOSIPHONATE CEPHALOPODS: FLOWER 45
further in the possession of a hyponomic sinus. In form they are rather typical of Valcouroceras except for these details, and ex- hibit the ontogenetic modification of section from compressed to depressed, that characterizes the Lower Ordovician genus.
Valcouroceras bovinum Flower, n. sp. Plate 4, figs. 2-3; 9-10
Conch strongly cyrtoconic, rapidly expanding, the living cham- ber contracting in the mature portion and becoming slightly com- pressed gerontically. The species is represented in our material by two specimens illustrating different stages of growth.
The holotype consists of an essentially complete mature liv- ing chamber and a portion of the phragmocone retaining the siphuncle. The living chamber has a basal height and width of 39 mm. Ina dorsal length of 25 mm. and a ventral length of 52 mm., the aperture is attained which is considerably oblique from the axis of the last septum, which was nearly transverse, and also from the axis of the shell. The height across the aperture is 45 mm., the width, 37 mm. The radius of curvature of the ventral profile is variable over the living chamber, but averages 50 mm. The phragmocone has sutures which in the mature shell slope only slightly forward on the ventral side. The siphuncle, close to the mature living chamber, is made up of broadly round- ed segments, somewhat scalariform in vertical section. A well- defined organic lining is seen within the siphuncle, quite typical of actinosiphonate deposits in a median vertical section. It was not possible to make a cross section to determine the presence or number of rays, but they are obviously not strongly developed.
The paratype is a slightly younger specimen( expanding from a compressed section of 22 mm. and 24 mm, at the base to a cir- cular section of 32 mm. at the base of the living chamber. The 25 mm. of phragmocone on the venter contains six camere. The shell attains a height of 42 mm. and a width of 39 mm. in the basal 15 mm, of the living chamber. The living chamber is in- complete, and has a maximum lateral length of 35 mm. Just be- yond the base the sides become convex and the shell apparently assumes a compressed condition.
Discussion.—This is a large relatively rapidly expanding shell. By this it can be differentiated from not only smaller rapidly ex-
46 BULLETIN 109 46
panding species, but also from the more slender Il’. lativentrum (Ruedemann).
Types.—Holotype, University of Cincinnati Museum, No. 24169; paratype, No. 24170.
Occurrence.—Valcour limestone, upper Chazyan, Little Monty Bay, southeast of Chazy, N. Y.
Valcouroceras obesum Flower, n. sp. Plate 4, fig. 5
Conch strongly curved, faintly depressed in earliest part, with diameters of 18 mm, and 22 mm., expanding in 40 mm. ventral- ly to 30 mm. and 32 mm., where the conch is faintly compressed at the base of the living chamber. In the basal third of the liv- ing chamber, the diameters increase to their maximum of 32 mm. and 36 mm, contracting toward the aperture which measures 28 mm. and 34 mm. ,and is 50 mm. from the base of the living chamber as measured ventrally. Radius of curvature about 40 mim. for the ventral outline, but with curvature slightly greater on adoral half of living chamber.
Sutures rising adorally on venter, with shallow lateral lobes. Ephebic camere at a transverse diameter of 30 mm. measure 3 mm. in length, Siphuncle close to venter, compressed at sep- tal foramen, its structure in section not observed in this species.
Aperture incomplete, but definitely transverse to axis of conch and without hyponomic sinus. The surface bears transverse lines of growth. Section with the venter obscurely subangulate in basal half of living chamber and adoral part of phragmocone.
Discussion —Enough of this species is known to justify a re- censtruction of the form, and indicates clearly a breviconic cyrto- ceracone rapidly expanding apically, subcircular in earliest stage, faintly depressed in early ephebic portion, becoming more and more compressed over the living chamber which contracts slight- ly toward the aperture, contracting more laterally than vertically. An earlier portion of the specimen is preserved, which is too im- perfect for accurate measurement and consists of a portion of the phragmocone filled with calcite, which was impossible to extract from the limestone matrix.
The species is larger than l’, seeleyi, and is much more strongly curved, The dorsum is concave in portions of V. obe-
47 ACTINOSIPHONATE CEPHALOPODS: FLOWER 47
sum comparable in size to those of ’. seeleyi in which it is defin- itely convex. The dorsum becomes very faintly convex in /V. obesum only along the living chamber.
Type—Holotype, University of Cincinnati Museum, No. 22172.
Occurrence.—From the Valcour limestone near Little Monty Bay, Chazy, New York.
Valcouroceras cyclops Flower, n. sp.
Plate 2, figs. 4-6; Plate 3, fig. 7; Plate 5, figs. 11-12
This species, the largest in the Valcour limestone, may be dis- tinguished from all others by its large size. All specimens so far encountered are fragmentary, but two living chambers, both very poorly preserved are known, and a number of fragments from the adoral part of the phragmocone have supplied excellent ac- tinosiphonate deposits. Because of the fragmentary nature of the specimens, it has been considered necessary to describe them separately. The large living chambers are so poorly preserved that they are not figured.
The shell is compressed and the venter subangular in the early stages of growth. The section becomes depressed at a_ shell width of 75 mm., at the base of the mature living chamber. Two nearly complete living chambers are known. One preserves only one lateral surface. It has a ventral length of 120 mm., a uni- form radius of curvature of the venter of about 120 mm., and in- creases vertically from 60 mm, to 80 mm. in height in the basal two-thirds. The dorsum is missing adorally, but apparently ex- pansion continues to the aperture. This suggests that the speci- men may not be mature.
A second living chamber, somewhat flattened vertically by pressure, increases in its present condition from a height of 85 mm. to 90 mm., in a ventral length of 80 mm., and a dorsal length of 50mm. This specimen preserves the shell surface in part, and shows a broadly banded appearance, with the coarsest markings 5 mm. apart, but with finer ones irregularly spaced between.
The sutures are relatively simple, and essentially straight and
transverse, failing to slope forward on the venter as in most other species.
48 BuLLETIN 109 48
One early stage which is placed in this species because of the simple sutures and the rugose surface, a portion of a shell with a maximum length of 70 mm., shows the siphuncle in the basal portion. In this region the shell expands from 13 mm. and 15 mm. to 26 mm, and 27 mm., and the siphuncle, though cyrto- choanitic, is much more slender than in representatives of other species of comparable size.
Discussion.—In spite of the fragmentary nature of all shells so far encountered, it seems desirable to apply a name to this species which can readily be distinguished from its associates by its large size. Apparently early portions of the shell show a more gradual expansion of the siphuncle than do those of smaller and more accelerated species, nevertheless, extremely early stages still remain as undeterminable. This species, with Montyoceras titaniforme Flower and the endoceroids, largely Vaginoceras op- pletum Ruedemann, are the dominant Valcour species, at least in regard to size. The species is apparently not uncommon, but the extreme hardness of the rock makes it difficult to obtain. I have not figured the larger representatives of the species. All have very poor surfaces, and are of such a nature that they could not be photographed successfully. Further, reduced figures of such specimens are usually not satisfactory. The form can be reconstructed by the measurements given above, and the later portions of phragmocones may be readily recognized by examina- tion of the siphuncle which is compressed at the septal foramen and equipped with good actinosiphonate deposits which are amply illustrated here.
Types.—Syntypes, University of Cincinnati Museum, Nos. 24174-0.
Occurrence.
From the Valcour limestone near Little Monty Bay, southeast of Chazy, New York.
Valcouroceras cf. seelyi (Ruedemann) Plate 4, fig. 11
Oonoceras seelyi Ruedemann, 1906, New York State Museum, Bull. 90, py 496-7) is ole ple 38. figs. 7-11. One specimen figured here is referred to this species with doubt. It agrees with the original description in the short rapid- ly expanding and only slightly cyrtoconic shell, but represents
49 ACTINOSIPHONATE CEPHALOPODS: FLOWER 49
a younger stage than the known figured specimens and has a considerably simpler siphuncle, The phragmocone expands ver- tically from 14 mm. to 27 mm. in a ventral length of 20 mm. and a dorsal length of 9g mm. The shell is faintly compressed in sec- tion, the width being 1 mm, less than the height at both ends of the phragmocone, though the venter is not much more narrowly rounded than the dorsum. There are seven camere in the phrag- mocone, and in the adapical five the siphuncle is seen in vertical section. The segments are similar in form and structure to those shown in text figure 2b. Deposits form a thickening of the con- rectine® ring, but fail to show any actinosiphonate rays.
Figured specimen.—University of Cincinnati Museum, No.
24190.
Valcouroceras, sp. 1 Plate 4, figs. 4, 6
Under this designation are figured two specimens represent- ing small phragmocones of lalcouroceras, which cannot be con- nected with any mature living chambers. The maximum size of this species is unknown, One of the specimens is relatively complete for the length of 25 mm. on the venter. The shell is compressed, the venter more narrowly rounded than the dorsum. It expands from 7 mm. in width and 8 mm. in height at the base to 17 mm. in height normal to the septum and a width estimated at 15 mm. The adoral six camere occupy a length of 14 mm. The siphuncle is close to the venter. Its structure has not been studied in section, but the aspect of the shell at the adoral end of the specimen indicates clearly that some organic lining is de- veloped which is a darker gray than the calcite which occupies the rest of the shell.
Similar in all respects but slightly smaller is a second speci- men which has been sectioned vertically. This increases in height from 4 mm. to 14 mm. in a ventral length of 26 mm. The siphuncle lies close to the ventral wall. The segments are slight- ly convex on the ventral side and are nearly angular and scalari- form on the dorsal side. The dorsal side of the siphuncle is thickened by an accessory deposit, some of which seems to be on the outside of the original connecting ring instead of exclusively on the interior. The earliest segments are more slender than the others, and approached very closely the suborthochoanitic pat- tern shown in text figure 2A.
50 BULLETIN 109 50
Figured specimens.—University of Cincinnati Museum, Nos. 24180, 24173.
Occurrence.—From the Valcour limestone, upper Chazyan, from Little Monty Bay, southeast of Chazy village, New York.
Valcouroceras, sp. 2 Plate 4, fig. 1
This specimen, included to show the diversity of early por- tions of Valcouroceras, a considerable number of which were en- countered, is more rapidly expanding than the above form, more arcuate, and has the sutures much less strongly inclined to the axis of the shell. The specimen is nearly circular at its base, 2 mm. in diameter, and increases in a ventral length of 32 mm. and a dorsal length of 22 mm., measured not quite to the adoral end, to 17 mm. and 15 mm. The venter becomes markedly nar- rower than the dorsum and the section is strongly subtriangu- lar at the adoral end of the specimen. The sutures are nearly straight and transverse. Laterally they are only very faintly curved, the convexity directed apicad. The shell surface is pre- served in part, and shows only vestigial lines of growth.
The radius of curvature is about 30 mm. for the venter.
The siphuncle at the adoral end of the specimen shows essen- tially the developmental stage illustrated in text figure 2B. No deposits are preserved. Apparently they were originally absent as the shell is well preserved and both camerz and siphuncle are filled with white calcite which would be expected to retain traces of the organic deposits. The deposits in these Valcour lime- stone specimens appear as a very dark-gray calcite which con- trasts strongly with the white infiltrated material.
Discussion.—This specimen, which approaches very close to the initial part of the shell, is clearly distinct from the two speci- mens described above as Valcouroceras, sp. 1, by the greater curvature, less inclined sutures, more rapid expansion and more strongly triangular section. Nevertheless, it is obviously not a specimen which shows any indication of an approach to maturi- ty, and the absence of a lining within the siphuncle suggests in addition that it may represent the phragmocone of an immature shell, It has not been possible to connect this specimen with any
Bill ACTINOSIPHONATE CEPHALOPODS: SLOWER 51
mature living chamber, which is considered necessary for the proper identification of a species. As a consequence it is con- sidered wisest not to propose a new specific name for this form. Figured specimen.—University of Cincinnati Museum, No. 24180. Occurrence.—From the Valcour limestone, upper Chazyan, from Little Monty Bay, southeast of Chazy, New York.
BIPECTINATE ACTINOSIPHONATE DEPOSITS
Only two genera and species of cephalopods are thus far known to have actinosiphonate deposits in which the rays are typically alternately bipectinate, that is, in which they are branched, and in which normally secondary branches are thrown off at regular intervals, first from one side of the main ray and then from the other. Teichert (1940) has figured such structure, though rather irregularly developed, for Danoceras subtrigonum of the Buchan limestone of Victoria, Australia. This species I have not seen, and all that is known of its structure is contained in Teichert’s description and figures. The rays of this form are branched, sometimes with alternative secondary branches, but often the secondary branches are as long as the main stipe, and like it may be divided. Bifurcation of the main stipe into two equal branches may also occur.
The single Ordovician cephalopod thus far known to have similar deposits, at least insofar as the cross section of the shell is concerned, is described below as Actinomorpha pupa. The siphuncle has been studied by means of a longitudinal section ground normal to the vertical axis of the shell, and two cross sections taken from near the adoral end of the siphuncle.
The longitudinal section, shown in Plate 3, figure 5, and en- larged in Plate 3, figure 2, is represented here by a section which does not attain the very center of the siphuncle; therefore the rays cut across it obliquely. The rays in these sections are rep- resented by the dark lines, while the remainder of the siphuncle is filled by buff-colored matrix. The longitudinal sections show that while the rays are often crowded at the region of the septal foramina, and some disappear there, enough can be traced
52, BuLLETIN 109 52
through this critical region to indicate beyond doubt that these deposits are essentially continuous throughout the length of the siphuncle. The apparent disappearance of some of the rays at this region is quite easy to understand in view of the nature of the rays as seen in cross section. The section may easily pass through some of the short branches, and even the main rays may shorten occasionally at the septal foramena so that they appear to vanish there in sections cut to the right level.
The longitudinal section is not in itself very revealing of the nature of the rays. This can be seen better in cross sections. Two such sections were made, that shown in Plate 3, figure 4 lying at the adapical end of the small piece near the base of the liv- ing chamber which can be clearly identified in Plate 3, figures 3 and 6, lying just orad of the portion of the phragmocone on which the siphuncle has been exposed by grinding of the venter. The section shown in Plate 3, figure 3 lies at the adoral end of the same piece. Here the structures have been considerably distorted as the result of the distortion which has affected the adoral end of the shell of this specimen, while the adapical end is relatively unmodified in form.
The cross sections show that the siphuncle wall, here consist- ing apparently of a connecting ring, is relatively thin. There is no differentiation of an organic lining of the siphuncle from the ring, and the two are almost certainly one and the same struc- ture, as has been found to be the case in other actinosiphonate cephalopods studied here.
The rays are formed of material darker than the matrix, and are essentially uniform in texture throughout. There is no indi- cation of a central axial structure as in Archiacoceras, and as also indicated in Danoceras subtrigonum (Teichert, photograph, also 1940). The rays are variable in form but are essentially described as bipectinate, being branched first on one side and then on the other. The rays vary in form, Sometimes second- ary branches may be lengthened so that they penetrate as far into the siphuncle cavity as the main stipe, and sometimes they may be branched. However, generally the bifurcation of the main stipe is not encountered, and secondary branching of a
or Pay
53 ACTINOSIPHONATE CEPHALOPODS: FLOWER
branch from the main stipe of the ray is not usually carried very far. One phenomenon which seems to be quite characteristic of the siphuncle of this genus is the presence of one or more short simple rays on the dorsal side and again on the ventral side of the siphuncle. In the two cross sections both of which are slightly distorted, as can be seen by the slightly irregular shape of the sec- tions, the simple short rays are not perfectly aligned, afid are dif- ficult to make out as they are shorter and smaller than other rays. They appear, however, to be a constant feature, and the only indication of a rough bilateral symmetry which can be seen in the siphuncles of this genus. These sections are adequate to show the mode of branching of the other rays of the deposit, and the two to- gether seem to show all possible variations from the simplest type in which short rays arise at regular intervals on alternate sides of a main stipe, like the mode of branching in some of the more generalized of the axonolipous graptolites.
From the structural similarity between <Actinomorpha and Danoceras it might appear that the genera may be related. This is a conclusion which is, however, unsafe, at least until more is known about the siphuncle of Danoceras, as it is not demonstrated there, though it seems likely from Teichert’s figures, that the de- posits are continuous from segment to segment. In form the genera are both compressed cyrtocones, with the siphuncle mar- ginal, but one is exogastric and the other is endogastric. Accord- ing to Teichert’s (1940) classification these genera would be placed in different families. While it is not impossible that ap- parently exogastric and endogastric genera may be very closely related, as sometimes seems to be the case of some of the cyrto- cones of the Silurian of Bohemia, the evidence is not strong enough in the present instance to suggest that the similarity of the actinosiphonate deposits of these two genera represents more than an accidental convergence.
Genus ACTINOMORPHA Flower, n. gen.
Genotype.—Actinomorpha pupa Flower, un. sp.
Shell strongly compressed in section, the venter slightly more
54 BuLLETIN 109 é 54
narrowly rounded than the dorsum. The shell is breviconic, ex- panding to a point just before the base of the mature living cham- ber and then contracting toward the aperture. In the early part of the shell the venter is faintly convex, the dorsum and the sides are essentially straight in profile until the maximum diameters are attained. Where the maximum width is attained the sides converge gradually, but remain only slightly convex to the aper- ture. The curvature of the venter remains fairly uniform. athie dorsal profile has not been observed but probably assumes a con- vex condition.
The sutures are essentially straight and transverse. The si- phuncle lies close to the venter, and is made up of rather broad segments which are cyrtochoanitic but expand relatively slightly within the camerz. The interior of the siphuncle contains well- developed actinosiphonate deposits which are continuous through- out the length of the siphuncle, and in which branched or pectin- ate processes extend inward from the margin toward the center of the siphuncle.
The aperture appears to be straight and transverse dorsally and laterally, but on the venter a conspicuous hyponomic sinus is de- veloped. The surface bears frequent low rounded ridges, rather irregular, which function as lines of growth, preserving the course of the sinus.
Discussion.—Superficially the holotype and only known spe- cies is faintly suggestive of the genus Newmatoceras in form, par- ticularly in the increasing convexity of the ventral profile near the aperture, giving the shell a slightly humped appearance. How- ever, the earliest stage fails to show that the shell was truly and strongly cyrtoconic as in Neumatoceras, but instead was straight or nearly so to the apex. Newmatoceras is described as having a ventral siphuncle in which the segments are “faintly expences a condition which I have found to be true of some species which are typical of Newmatoceras in external form. However, Foerste (1935, pl. 2, fig. 1) has shown in N. nutans Foerste a siphuncle which is broad but tubular and orthochoanitic. No other genus seems to resemble this one closely. Perhaps the only other one similar in aspect is the nearly straight compressed breviconic
or Or
5o ACTINOSIPHONATE CEPHALOPODS: FLOWER
Dowlingoceras Foerste (1928) which is similar in the profiles of dorsum and venter and differs further in the absence of a hypo- nomic sinus. The siphuncle is similar to that of this genus in form, but no actinosiphonate deposits have been recognized.
Actinomorpha pupa Flower, n. sp. Plate 3, figs. 2-6
The holotype, preserving the greater part of a mature shell, is a faintly exogastric brevicone 80 mm. in length. The section is compressed, the venter narrower than the dorsum, expanding in the greater part of the length of the phragmocone from a height of 21 mm. and a width of 18 mm. to a height of 40 mm. and a width of 33 mm. This occurs in a ventral length of 34 mm., and attains the greatest width of the shell. Over the next two cam- ere, 7 mm. in length, the sides become markedly convex, and in the remaining 40 mm. of the living chamber, the sides converge to a width of 20 mm., which was probably originally greater as there is clear evidence of compression of the living chamber after death. The ventral profile increases in curvature as it approach- es the aperture. The dorsal profile is unknown beyond the adoral portion of the phragmocone. It probably became slightly con- vex as the aperture was approached. The sutures are straight and transverse. The camer are nearly uniform in depth throughout, varying only from 3.5 mm. to 4 mm. on the venter as shown by the length of the segments of the siphuncle. The sutures are not, for the most part, preserved on the type; the only ones being clearly shown are those near the base of the living chamber.
The siphuncle lies close to the venter. It is made up of rather broad segments which expand within a camera from 3 mm. to 5 mm. where the length of a segment is 4 mm. The septal necks are very short and recurved. The connecting rings are evenly convex in longitudinal section. Actinosiphonate deposits are well developed in the siphuncle. These are described in detail follow- ing the description of this species.
56 BuLLeTIN 109 56
The aperture bears a prominent hyponomic sinus on the convex siphonal ventral side of the shell. The surface is marked by low rounded distant transverse ridges which follow the course of the hyponomic sinus throughout the early growth stages. Four ridges occur in a length of 10 mm., but there is some variation in their spacing. They do not appear to be preserved at all on the internal mold.
Discussion Although in form this species is remotely similar to Neumatoceras, it can be distinguished not only by the struc- ture of the siphuncle, but also by the form of the shell. The great- est height of the shell is not attained, as in that genus, considerably apicad of the base of the living chamber. The sutures do not rise strongly orad from dorsum to venter, and the early part of the shell is not strongly cyrtoconic as in Newmatoceras. Neverthe- less, Actinomorpha is probably closer to Newmatoceras in form than to any other genus. The only other comparable genus is Dowlingoceras Foerste (1928, p. 43) which is a compressed straight brevicone, somewhat similar in the outline of the segments of the siphuncle, but lacking two important features of Actino- mor pha, the hyponomic sinus and the actinosiphonate deposits.
This remarkable species has been known to me for some years, but I have delayed its description largely because of uncertainty as to its origin, in the hope of obtaining additional material which might settle this problem. It has suffered all the vicissitudes which can come upon a specimen from an old collection. When first discovered in the collections of the University of Cincinnati Mu- seum, it was labeled and catalogued as “Gonioceras anceps (Hall), Black River.”’ The manifest absurdity of the determination made it seem likely that the approximate horizon data might be equally wild. However, inspection of the catalogue showed that the next specimen was labeled “Gomphoceras, Black River” and proved to be a good Gonioceras occidentale. It is quite evident that prior to cataloguing the labels of these two specimens were inter- changed. Further, it makes it reasonably certain that both are from approximately the same horizon and locality. G. occiden- tale is a Platteville species, known from Wisconsin and Minne- sota, and it seems probable that Actinomorpha pupa is from the
57 ACTINOSIPHONATE CEPHALOPODS: FLOWER 57
same horizon and region. The two agree in lithology to the ex- tent that both are preserved in a light yellow dolomite. A. pupa, however, is preserved in fine-grained material, probably higher in calcium content, and lacks the saccharoidal texture of most Platteville specimens.
Holotype.—University of Cincinnati Museum, No. 8969.
Occurrence.—Unceertain, as noted above, probably Platteville of Wisconsin or Minnesota.
AGTINOSIPHONATE DEPOSITS OF ARCHIACOCERAS
Two specimens of Archiacoceras subventricosum from the Middle Devonian have supplied the basis of the following ob- servations. QOne specimen was studied by means of camera lucida drawings of serial sections in the New York State Museum, and a second specimen was procured for a similar study at the Uni- versity of Cincinnati.
Archiacoceras Foerste (1926, p. 346), based upon Phragmo- ceratites subventricosus d’Archiac and de Verneuil, is a com- pressed endogastric shell. The genotype is apparently known only from the phragmocones. The shell is cyrtoconic, com- pressed, the sutures are curved on the sides, the convexity being directed apicad, and extend farther forward on the convex side than on the concave side. The position of the siphuncle on the concave side of the shell is responsible for the generally accepted interpretation of the shell as endogastric. However, this is very questionable as the siphonal side of the shell bears a very well- defined septal furrow (Flower, 1939) which is known to be ex- clusively a dorsal feature in other cephalopods, including Naw- tilus. It should be noted that nothing is known of the aperture of the shell of this species. Apparently no other species than the genotype has been placed in Archiacoceras. Other presumably endogastric compressed shells are: Protophragmoceras Hyatt, a Silurian genus without known actinosiphonate structure; Endo- plectoceras Foerste 1926, also Silurian, is more slender, and has a more broadly expanded siphuncle; Danoceras Foerste 1920, is typically slightly gibbous over the living chamber and less rap- idly expanded. The Silurian genotype has a rather slender si-
= BULLETIN 109 22
phuncle, containing actinosiphonate deposits but Teichert (1940) has recognized the genus in the Middle Devonian of Victoria, Australia, where it is represented by a species with a considerably larger siphuncle. Probably more similar in form to Archiacoceras than any other genus is Alpenoceras Foerste based upon A. ulricht Foerste of the Alpena limestone. Congeneric are several spe- cies from the Winnipegosis dolomite, of which only A. occiden- tale Whiteaves is described. Within this genus the siphuncle is close to the concave side of the shell and is made up of expand- ed segments. However, the siphuncle contains a continuous lin- ing without the development of rays forming an actinosiphonate deposit. This condition has been found in both the genotype and A. occidentale.
The actinosiphonate deposits are shown best by cross sections of the siphuncle. There is a thick organic lining which cannot be differentiated from the connecting ring and which is believed to arise from it. From this lining toward the center of the siphun- cle there project numerous radial processes. These are gener- ally simple, their sides subparallel but irregular, and the tips rounded and slightly inflated. These are sometimes divided, but division is irregular and never attains the alternating bipectinate pattern of Actinomorpha or of Danoceras as reported by Teichert. In opaque section some structure can be detected in the rays. In thin section (Pl. 4, fig. 1) it can be seen that the outer part of the deposit is composed of finely granular material, which cannot be differentiated from the connecting ring. This composes three-fourths the width of the lining of the siphuncle, or may perhaps be more properly considered a thickening of the siphuncle wall itself. An inner thin band is clearer and a lighter yellow. Often this is not sharply set off from the thicker part of the lining, but in some places a definite line can be seen which represents a definite boundary between the two. This is not apparent in all cross sections, and often cannot be traced around the entire circumference of a single cross section. (PI. 5, fig. 1).
The rays ordinarily show a clear differentiation of structure.
There is an outer rim of clear material. This encloses a central
rod as seen in cross section which may extend a variable distance
at the base into the siphuncle lining. In the distal inflated part
59 ACTINOSIL HONATE CEPHALOFODS: FLOWER 09
of the ray the rod may continue to a point not far from the tip, but is always inclosed in the light-colored lining. The rod is not always clear as a distinct entity in this region from a menisci- form or oval mass of darker, coarser grained material. This may often appear to consist of several concentric layers which are apparently original. The three rays shown in Plate 5, figure 1 show some of this variation. That at the left shows the in- flated menisciform material within the broadened tip of the ray, but only a vestige of the central rod in this area. The central one shows the rod and several concentric layers in the menisciform structure before the outer thin lining which is continuous with the marginal clear layer of the siphuncle wall. The third shows the rod clearly but there is poor differentiation between the menisciform mass and the lining. (Fig. 2g.)
The number of rays appears to increase gradually orad in the siphuncle. However, the rays are generally continuous from segment to segment. Major rays remain fairly constant numer- ically in a suite of serial sections, although they are supplement- ed erratically by secondary rays which are not prolonged along the axis of the siphuncle for any distance, but instead are essen- tially short rodlike projections. However, in any one cross sec- tion it was not always possible to distinguish the major rays from the secondary ones, as they may upon occasion equal one another in length and structure. In general the shorter rays fail to show the inflation at their tips which is so well developed in the longer ones. Of the two specimens studied by a series of sections pass- ing from one camera to another, the major rays appeared not only constant, but perfectly aligned from segment to segment. One showed 19 rays in most serial sections, though the number varied from 18 to 20. In the other specimens, that illustrated on Plate 6, the rays were more numerous, varying from 36 to 38. These sections were taken through two segments near the adoral end of a large individual. In the adapical portion of the same shell, the rays averaged only 18 in number. Clearly the rays in- crease in number orad. The increase in the number of rays is brought about in part by the interpolation of additional rays. It is not certain, however, that rays may not also be produced by bifurcation.
60 BULLETIN 109 69
Cross sections show a uniformity of the number and arrange- ment of rays from segment to segment. Longitudinal sections, however, show commonly the appearance of discrete segmental
series of rays which are massed about the septal foramen, and.
extend from there orad into the segment, but not apicad. This appearance was due to the nature of the longitudinal sections, which do not cut the rays parallel to their axes, but are slightly oblique to the plane of the rays, and cut them only near their tips. As the rays extend farther centrad in some regions of the siphun- cle than in others, this presents the aspect of discrete segmental deposits (Pl. 6, figs. 2-3). However, a section which is marked- ly eccentric, will show that a single ray is continuous at least throughout the central part of each segment. (PI. 6, fig. 1.) In order to determine the exact nature of the rays, it was necessary to secure a series of serial cross sections of the siphuncle. Select- ed sections from such a series are shown in Plate 6, figures 4-9.
Figure 4 is taken near the adoral end of a segment. The lining of the siphuncle is strongly developed and from it project a se- ries of rays toward the center of the siphuncle. These belong to the segment in which the section was taken, as shown by the low- ermost transverse line drawn on PI. 6, fig. 3, which indicates the position of this section. However, on the right side of the section, which is very slightly oblique, extending farther orad on the left than on the right, the deposits of segment 1 lie in contact with de- posits of segment 2. Farther orad, as shown on the left side, fusion is complete and the boundary between the two cannot be made out structurally, though it is evident on the basis of outline alone, Fur- ther, here the deposits of segment 2, the adoral segment, have ex- panded laterally to form a continuous ring of organic material within the deposits of segment 1.
Figure 5 shows a section only slightly farther orad. It differs from figure 4 mainly in that the central ring belonging to the adoral deposit is better formed. An intermediate section in which the ring is complete is omited.. As can he seen fom figures 4 and 5, the rays of the two deposits, apparently of seg- mental origin, are perfectly aligned and continuous.
Figure 6 is taken at the adapical end of the septal foramen,
61 ACTINOSIPHONATE CEPHALOPODS: FLOWER 61
and shows the constriction of the siphuncle. On the right side there is a trace of the outer rays, because that side of the section as ground lies slightly farther apicad than the left side, as was the case in figures 4 and 5.
Figure 7 passes through the septal foramen. The light area sur- rounding the siphuncle cavity marks the part of the section which cuts through the adnate connecting ring and the septal neck, which is essentially recumbent as can be seen in figures 1-3. These structures are not clearly differentiated in opaque sections,
Figures 8 and 9 are taken orad of the septal neck. The cav- ity of the siphuncle assumes its former proportions, though ex- panding on the upper side (probably ventral), which is farthest from the shell wall, as shown in figure 8. Figure 9 illustrates a condition which will persist orad from the position of the section early in the entire length of the segment of the siphuncle, as was ascertained by the grinding of further sections which are not illustrated here inasmuch as they failed to show additional morphological features.
In these cross sections, which are oriented with the dorsal side down, and are continued to the shell wall, an excellent check on differentiation of original structure against replacement phe- nomena was supplied by the variable mode of preservation shown within any single section. One side of the siphuncle, that on the right in figures 4-9, was filled with light calcite, which continued over the ventral part of the shell to the shell wall, and appears white in most of our sections. The left side of the shell, how- ever, was filled with matrix.
From these sections it is necessary to conclude that the de- posits of the siphuncle of Archiacoceras first of all are nothing more than projections from a much thickened connecting ring. As may be expected from their origin, their linear extent in the siphuncle is controlled by the arrangement of the serially repeat- ed connecting rings. The deposit is heavy at the adapical end of the ring, where it may form an annulosiphonate ring fused with and supported by the rays belonging to the next adapical con- necting ring. A remarkable feature is the continuity and align- ment of the rays of adjacent metameric deposits.
62 BULLETIN 109 62
This type of structure is much more complex than that of Valcouroceras, and there seems to be no parallel for it in the complex but continuous rays of Actinomorpha. It iS not ste prising to find that the Ordovician genera exhibit a simpler structure. The taxonomic significance of the structure of Archiacoceras is unfortunately a matter only for conjecture until similar studies have been made known the structure of some of the contemporary and possiby related genera.
DISCRETE ANNULOSIPHONATE DEPOSIES
The three genera discussed above are all examples of a type of actinosiphonate structure which extends from segment to seg- ment. They are not uniform, and may not be homologus struc- tures, for in Archiacoceras they are apparently the fusion of seg- mental types, even though they may have been formed about con- temporaneously ontogenetically, while in Valcouroceras and Actinomorpha there is no reason to believe that the deposits are not truly continuous without any metameric origin.
Likewise the types of deposits grouped here as discrete acti- nosipnonate structures are diversified and almost certainly or- iginated independently of one another. The earliest of these discrete deposits, which are differentiated from the continuous septal foramina, and rarely meet and never fuse, are found in ones mainly in that the rays are confined to the regions of the Diestoceras Foerste. This genus is typically developed in the true Richmond, but is widespread and perhaps attains its maxi- mum size as well as diversity of structure in the large series of disconnected deposits ranging from the Fremont limestone of Colorado and the Big Horn formation north through the Ordo- vician Liskeard formation of Lake Timiskaming, the Red River series of Hudson Bay, the Whitehead formation of Gaspé, nu- merous Ordovician outliers of the arctic archipelago, of which the more important are in Baffin Land, and the Cape Calhoun formation of Greenland. Teichert (1934, 1937) has already pre- sented a summary of the essential features of this genus based upon a study of D. pyriforme Troedsson of the Cape Calhoun
a ———
63 ACTINOSOPHONATE CEPHALOPODS: FLOWER 63
formation, and D. scalare of the Richmond of Anticosti.
The structure is evidently very complex. Rays spring mainly from the region of the septal foramina, and extend orad and apicad into the expanded segments of the siphuncle. Some rays apparently also spring from the wall of the siphuncle within the expanded part of the segments. The structure is evidently com- plex, and must be approached by the use of carefully made serial sections.
In contrast to the structure of Diestoceras, the Brevicocera- tide of the Devonian show a much simpler deposit. This is best known for Brevicoceras and for Eleusoceras, both of which have been illustrated in longitudinal sections by the writer (Flower, 1938, pl. 1, fig. 1; pl. 3, fig. 2). These genera show deposits which do not project so far orad and apicad of their origin as do those of Diestoceras, and they are obviously much simpler in form. Additional material of Elewsoceras has failed to preserve these structures properly for section, but several sections were taken from the holotype of Brevicoceras pompeyense Flower at the region of a septal foramen. The actinosiphonate rays are attached to the siphuncle wall only at the foramen, as shown in text figure 2 F, and each is bifid. Sections farther away from the foramen show these deposits to extend orad and apicad, but where this occurs they are free from the siphuncle wall, and are rather irregular in structure. Naedyceras and its allies occasionally show structure which is similar but less complex, inasmuch as the deposits do not extend orad or apicad into the camere for any appreciable length. These forms are discussed and illustrated by the writer in another work, now submitted but unpublished. At the risk of creating nomenes nuda I note here that Gyronaedyceras validum (Hall) has yielded such deposits, which are also shown in various species of Naedyceras, though more poorly preserved, and similar rays are characteristic of Stereotoceras Flowers ms., in which they are particularly well developed.
64 BULLETIN 109 64
CONCLUSIONS
Actinosphonate deposits have appeared at least three times independently in the history of nautiloid development: in the closely allied Chazyan genera Minganoceras and Valcouroceras, again in Oocerina in the Silurian and in the Brevicoceratide, which developed such deposits in Upper Silurian time. Probably other similar cases await discovery or confirmation. As polyphy- letic structure, actinosiphonate deposits are not in themselves an adequate criterion for a major division of the nautiloids. However, there is much variation within actinosiphonate deposits, and some of these types seem to be characteristic of restricted genetic groups. It is highly unlikely that few types studied closely in the present work have exhausted the possibilities for morpholog- ical variation within those structures which have been lumped together under the term actinosiphonate. Briefly, the following types have been recognized here:
I. Deposits consisting of a thickening of the connecting ring producing simple rays which are continuous from segment to segment, This is typical of Minganoceras, Valcouroceras and those Upper Ordovician species at present assigned to ll’ether- _byoceras. From the extant figures, many Silurian actinosipho- nate cephalopods fall in this category.
II. Deposits consisting of alternately bipectinate rays, appar- ently continuous. Only two examples of this type are known, probably unrelated, Actinomorpha Flower of the Ordovician, and Danoceras as reported by Teichert (1040) for a Devonian species. These are quite probably not closely related.
III. Deposits of apparently segmental origin, but fused and perfectly aligned, as exemplified by Archiacoceras, What other genera show similar structure is as yet unknown.
IV. A deposit consisting of a lining of the siphuncle and irreg- ular complex processes. This is known only from Diestoceras of the Ordovician, which seems so different from contemporary actinosiphonate genera that it probably developed these structures independently.
V. A deposit consisting of a lining of the siphunele and shorter
65 ACTINOSIPHONATE CEPHALOPODS: FLOWER 65
simpler processes arising from the septal foramen, usually bifur- cated, always discrete, and never markedly complex. This is characteristic of the Devonian Brevicoceratide, and has been observed in Naedyceras and its allies, Brevicoceras, Eleusoceras, and imperfectly in Foersteoceras, as well as in several related genera descriptions of which are in press.
From the polyphyletic origin and seemingly erratic distri- bution, it is evident that actinosiphonate deposits must be the re- sult of excess calcification, resulting in form-types which are built in accordance with pre-existing structures in the soft parts of the siphuncles. The rough similarity of the form-types in- dicates approximate structural similarities of organization on the siphuncles of these various cephalopods, often not closely re- lated, but differences exist which may be of great morphological and taxonomic significance when they are better known.
Actinosiphonate deposits fail to show the ontogenetic pro- gression from one part of the shell to another which is to be expected in a series made up of similar repeated segmental parts, such as have been found in the annulosiphonate deposits of the Actinoceroidea, Pseudorthoceratide and orthochoanitic orthoceracones. This necessitates the conclusion that such de- posits were formed during a relatively short and rapid period of growth. Otherwise such ontogenetic progression would certainly have been found. The absence of deposits in many shells of normally actinosiphonate species is to be explained in terms of growth stages. Actinosiphonate deposits appear only in gerontic or near gerontic shells, and are deposited rapidly within siph- uncles. Specimens which represent neanic or early ephebic growth stages may be expected to lack these features. This conclusion may require some slight emendation. It is doubtful whether there is any sharp demarcation between the growth stages. In some instances actinosiphonate structure is accom- panied by other manifestations of the excess deposition of cal- careous material within the shell. However, it 1s suspected that in some instances actinosiphonate deposits may precede most other types of gerontic calcification, at least in the genus Her- kimeroceras Foerste of the Upper Silurian. It is eminently de-
66 BuuuetTIn 109 66
sirable that this matter be investigated further. The present hypothesis, however, seems to be the only one which will explain adequately the absence of normal ontogenetic progression and the widespread though perhaps not universal correlation between actinosiphonate structure and other deposits which are clearly a manifestation of late maturity and old age.
Within the earliest stages of actinosphonate species no true actinosiphonate deposits are developed. Further, some small mature species congeneric with a closely related to typically actinosiphonate species may lack the deposits throughout the entire phragmocone. There is not yet adequate evidence to ex- plain this phenomenon. It might be that in Valcouroceras small species fail to attain actinosiphonate structure because they are phylogenetically more primitive than their larger and longer lived relatives. However, this hypothesis cannot be invoked to explain indentical phenomena in the small species of the Devonian genus Brevicoceras which is developed from gyroceraconic and trochoceroid shells of considerable size which have well-developed actinosiphonate deposits.
Actinosiphonate deposits differ widely from the septa and other true shell structures in their color, and texture, and obviously have undergone a rather different history of preservation. This leads to the conclusion that they are not true shell structures, but like the connecting ring must have a different origin. Fur- ther, the deposits are believed to be developed by a thickening of the connecting ring itself, for while various structures may be differentiated in actinosiphonate deposits, the thin sections thus far examined fail to show a differentiation of the deposits from the connecting ring.
67 ACTINOSIPHONATE GEPHALOPODS: FLOWER 67
REFERENCES
Flower, R. H.
1941. Notes on structure and phylogeny of eurysiphonate cephalopods. Paleontographiea Americana, vol.3, No.15, 56 pp., 3 pls., 3 figs.
1941. Development of the mixochoanites. Jour. Paleont., vol. 15, pp. 523-548, pls. 76-77, 20 text figs.
1941. Relationship of the Devonian trochoceroid cephalopods Sphyrado- ceras and Naedyceras. Geol. Soc. Amer., Bull., vol. 52, p. 1976. —.Middle Devonian cephalopods of New York. (Submitted 1942) New York State Museum, Bulletin.
Foerste, A. F.
1926. Actinosiphonate, trochoceroid and other cephalopods. Denison Univ. Bull., Sci. Lab., Jour., vol. 21, pp. 285-384, pls. 32-53.
1938. Cephalopoda in Twenhofel. Geology and paleontology of the Min- gan Islands, Quebec. Geol. Soc. Amer., Special Papers, No. 11, 32 pp., 24 pls.
Hyatt, A.
1884. Genera of fossil cephalopods. Boston Soc. Nat. Hist., Proe., vol. 22, p. 203-338.
1900. Cephalopoda in Zittel- Eastman Textbook of Paleontology, vol. 1, Ist. ed., p. 502-592. ;
Ruedemann, R.
1906. Cephalopoda of the Champlain Basin. New York State Museum,
Bull. 90, 611 pp., 38 pls., 57 text figs. Strand, T.
1935. The Upper Ordovician cephalopods of the Oslo area. Norsk Geol.
Forening, Bind 14, (1934) pp. 1-118, pls. 1-15. Teichert, C.
1933. Der Bau der actinoceroiden Cephalopoden. Paleontographica, Bd. 78, Abt. A, pp. 111-230, pls. 8-15.
1934. Untersuchungen an actinoceroiden Cephalopoden aus Nordgron- land, Bd. 92, nr. 10, pp. 1-48, 22 figs.
1939. Nautiloid cephalopods from the Devonian of western Australia. Royal Soc. Western Australia, Jour., vol. 25, pp. 103-12, O, pls. 1-2, 2 text figs.
1940. Actinosiphonate cephalopods (Cyrtoceroidea) from the Devonian of Australia. Royal Soc. Western Australia, Jour., vol. 26, pp. 59-74, pl. 1-4, figs. 1-2. :
Ulrich, E. O. and Foerste, A. F.
1933. The earliest known cephalopods. Science, n. ser., vol. 78, pp. 288- 289.
Ulrich, E. O., Foerste, A. F., Miller, A. K. and Furnish, W. M.
1942. Ozarkian and Canadian cephalopods. Part I. Nautilicones. Geol. Soe. Amer., Special Papers, No. 37, 157 pp., 57 pls.
68 BULLETIN 109 68
NEW ORDOVICIAN CEPHALOPODS OF EASTERN NORTH AMERICA
The descriptions brought together here include Chazyan and Black River cephalopods of the University of Cincinnati Museum. These include the following genera and species:
Actinoceras arcuanotum Flower, n. sp. Tyrone limestone, Kentucky.
Eorizoceras platyceroides Flower, n. sp. Chazy limestone, Lake Champlain.
Eotripteroceras minutum Flower, n. sp. Chazy limestone, Lake Champlain.
Graciloceras longidomum Flower, n. sp. Chazy limestone, Lake Champlain,
Centrocyrtoceras mozolai Flower, n. sp. Chazy limestone, Lake Champlain.
Trocholites rucdemanni Flower, n. sp. Chazy limestone, Lake Champlain.
Trocholites gracilis Flower, n. sp. Chazy limestone, Lake Champlain.
These descriptions are published at this time because it is felt that further delay in the appearance of these forms may seriously interfere with the progress of the study of the Paleozoic cephalo- pod. Originally it was intended to append to these descriptions a considerable number of new forms of the Cincinnatian. How- ever, the arrival of much additional material has made it de- sirable to place these together in a separate and a more compre- hensive work devoted to the cephalopods of the Upper Ordo-
vician of the Cincinnati region.
Genus ACTINOCERAS Bronn
Actinoceras arcuanotum Flower, n. sp. Plate 2, fig. 7
The holotype represents a mature individual of a relatively small and slender species, consisting of a phragmocone 160 mm. long and living chamber 120 mm, long. The specimen expands from a width of 34 mm. and an estimated height of 25 mm. to 46 mm. and 34 mm. in a length of 90 mm.; in the remaining 60 mm. of the phragmocone the conch attains 58 mm. and 39 mm. The living chamber contracts gradually to the aperture, the venter being straight, but the dorsum and the lateral outlines slightly curved, so that the apertural end measures 30 mm. and 50 mm., and the living chamber has a fusiform appearance.
69 ACTINOSIPHONATE CEPHALOPODS: "LOWER 69
In section the venter is slightly more flattened than the dorsum. The siphuncle lies ventrad of the center, and is very close to the ventral wall in the apical part of the shell. Here it has a width of 15 mm. at the septal foramen, and a height of probably about 12 mm. The septa are nearly straight and steeply inclined as seen in section. The sutures are unknown ventrally but describe lobes on the dorsum adorally. The camere occur four in a length equal to an adoral height of the shell and between five and six in a length equal to the adoral width in the adapical portion. Adorally six occur in a length equal to the width and four in a length equal to the height where the section measures 38 mm. and 30 mm. The gerontic camere are markedly shortened.
The siphuncle at the apical end is exposed in natural section. A segment expands from 16 mm. to 22 mm. and is 8 mm. in length. Annulosiphonate deposits are markedly thicker at the adapical end than at the adoral end and serve to illustrate clearly that such deposits do not extend the length of the phragmocone, but that they must be absent in some of the more adoral camerz.
Discussion.—This species is unlike any of the forms previously reported from this area. It can be readily distinguished from Actinoceras kentuckiense by the more gradual expansion of the shell and the more transverse sutures. _It can be distinguished from A. libanum Foerste and Teichert (1930, p. 245, pl. 34, figs. 1-2; pl. 57, fig. 5) by the more slender form and the strongly depressed section. The exact horizon of this species is not known with certainty, but lithology suggests that it is probably from the Tyrone, which is known to carry actinoceroids in a layer consid- erably above the “Birds eye” horizon, possibly Lowville in age.
Type.—Holotype, University of Cincinnati Museum, No. 22580.
Occurrence.—High Bridge, Kentucky, probably from _ the Tyrone limestone.
Genus EORIZOCERAS Flower, n. gen. Genotype.—Eorizoceras platyceroides Flower, n. sp.
Conch a rapidly expanding cyrtoceracone, moderately curved
70 BuLLETIN 109 70
adapically, becoming straighter adorally in the mature shell, the general aspect resembling that of a Devonian Platyceras. The section is faintly compressed in the early stage, with the dorsum and venter about equally rounded. This remains com- pressed ephebically but the section becomes subtriangular with the venter more elevated and more narrowly rounded than the dorsum. The sutures are straight, slightly oblique, sloping orad on the venter, the inclination increasing as the living chamber is approached. The siphuncle is small, close to the ventral wall, cylindrical, and empty. No cameral deposits are known. The surface bears well-defined transverse bands which continue across the venter with no indication of the usual hyponomic sinus. In addition, finer longitudinal markings are present on the genotype.
Discussion.—In torm this genus closely approximates fRiz- oceras as conceived by Hyatt, but differs in the absence of a hyponomic sinus and in the cylindrical siphuncle. The genus is evidently not related to the great mass of Ordovician and Silurian cyrtoconic cephalopods which are cyrtochoanitic, but is an in- pendent development of the orthochoanitic line. No _ closely similar orthochoanitic genera are known.
Eorizoceras platyceroides Flower, n. sp. Plate 5, figss)2-53
Conch cyrtoconic apically, becoming straight before the end of the mature (7) living chamber. The holotype represents a nearly complete specimen which describes an are of not over 70 degrees. The apex is oval, slightly compressed, venter and dorsum equally rounded, with a height of 3 mm. and a width of 2.8mm. This increases to a width of 17 mm. and a height of 18 mm. at the aperture where the venter is subangulate, the dorsum transverse, and the section obscurely subtriangular. This oc- curs in a ventral length of 30 mm., and an actual length of 28 mm. The phragmocone is 15 mm, in length and contains thirteen camere which increase only slightly in length when traced orad, from .5 mm. to .7 mm. The siphuncle is close to the venter, tubular, and apparently empty. The living chamber increases from a width of 8 mm. and a height of 9 mm. to 17 mm. and
fall ACTINOSIPHONATE CEPHALOPODS: FLOWER 71
18 mm. in a length of 18 mm. The last suture is inclined orad considerably on the venter, making an angle of about 20 degrees with the horizontal.
Surface with regular, distant rounded transverse lire and fainter longitudinal lire, the latter conspicuous only apically.
Discussion.—This species bears a superficial resemblance to some of the smaller associated species lalcouroceras, but may be distinguished by the orthochoanitic siphuncle, the shorter phragmocone and the lack of apertural contraction of the shell.
Type.—Holotype, University of Cincinnati Museum, No. 24186,
Occurrence.—Valcour limestone, upper Chazyan, from Little
Monty Bay, Chazy, New York.
Genus EOTRIPTEROCERAS Flower, n. gen.
Genotype—Lotripteroceras minutum Flower, n. sp.
Conch orthoceraconic, depressed in section, the venter more flattened than the dorsum. The mature sutures bear dorsal and ventral lobes. The siphuncle is located well ventrad of the center of the shell, and is perfectly tubular in outline. No deposits are known in the camere or in the siphuncle. The surface of the shell appears to be smooth.
Discussion—This genus resembles <Allumettoceras very strongly externally, but the tubular siphuncle shows that the similarity is purely isomorphic, and that no real relationship exists between the two genera. Instead this genus is apparently a specialized Michelinoceras. The only known representative as present is the genotype, of upper Chazyan age.
EKotripteroceras minutum Flower, n. sp. Plates5s Tess ton 14
The conch is small, orthoconic, depressed in section, rapidly expanding. In the 9 mm. of the holotype, the width increases from 8.5 mm. to 10 mm. and the height from 6 mm. to 7.5 mm. The sutures rise to low lateral saddles, and bear lobes on dorsum and venter. Five camer occur in a length equal to the adoral height of the shell of 7.5 mm. However, the normal depth of
72 BuLuetTIN 109 12
the camera may be somewhat greater, as the last two camere of the holotype appear to be slightly shorter than the others, which indicates that a mature condition is approached. If so, the ma- ture shell did not attain dimensions much greater than those shown by the type.
The siphuncle is tubular. Adapically it les 1.4 mm. from the venter, is .8 mm. in diameter and lies 4 mm. from the dorsum. Adorally it is the same in diameter, 1.8 mm. from the venter and 5 mm. from the dorsum.
Discussion.— The generic characters serve to distinguish this minute species. Irom early stages of Allumettoceras, it can be distinguished only by a study of the siphuncle in section, The siphuncle of Allumettoceras is still broadly expanded in a stage even earlier than that exhibited by the type of E. minutum. From most other orthoceracones the shell can be distinguished by the strongly depressed section and the rapid expansion.
Type— Holotype, University of Cincinnati Museum, No. 24187.
Occurrence.—From the Valcour limestone, upper Chazyan, of Little Monty Bay near Chazy, New York.
Genus GRACILOCERAS Flower, n. gen. Genotype.—Graciloceras longidomum Flower, n. sp.
Conch an exogastric cyrtoceracone of compressed section, ex- panding slowly and uniformly to the aperture. Living chamber very long, phragmocone in the known species much shorter than the living chamber. Sutures oblique, rising orad on the ventral side, developing slight lateral lobes. Septa shallow horizontal- ly, deep vertically. Siphuncle close to venter, orthochoanitic, empty. Apical camerze deeper than those following, slightly in- flated, possibly representing a “‘protoconch”’.
Discussion.—This genus is erected for the reception of a single Chazyan species. Aside from the remarkable length of the living chamber and the shortness of the phragmocone, the genus can readily be distinguished by its other features. Indeed, there are
73 ACTINOSIPHONATE CEFHALOPODS: FLOWER 73
no Ordovician or younger orthochoanitic cyrtoceracones with which it is at all comparable. The genus seems to be comparable with some Canadian cyrtoconic genera which are little known internally. Compressed Canadian cyrtoceracones of exogastric curvature comprise Bassleroceras, Dwightoceras, and Dyscrit- oceras. Of these Dwightoceras possesses a very large siphuncle, and is almose certainly eurysiphonate in its affinities and is pos- sibly an endoceroid. Bassleroceras is a slender compressed conch with a long phragmocone and a_ short living chamber which is very different from Graciloceras in aspect. Dyscritoceras which is more similar in the feaures of the phragmocone is brev- iconic, the living chamber contracted slightly at the aperture. The details of siphuncle structure of none of these genera are adequately known. The wall of the siphuncle of Graciloceras has not been studied in thin section, but appears to possess thin simple connecting rings of the stenosiphonate pattern.
While the siphuncle wall is not clearly preserved it is evident that the connecting ring is thin. The segments of the siphuncle appear to be suborthochoanitic rather than tubular. The seg- ments are extremely short in proportion to their diameter, and expansion is very slight.
Fig. 3. Graciloceras longidomum Flower, n. sp. A. Section of a speei- men showing a deep initial chamber, but cutting obliquely through the specimen as shown by the siphuncle. B. Section from holotype. The adoral end of the specimen is a natural weathered section. The adapical end was ground parallel to the cylindrical siphunele.
74 BULLETIN 109 fic
Graciloceras longidomum Flower, n. sp. Plate 4, figs. 7, 8; text fig. 3
The holotype, the most complete specimen preserved, presents a natural longitudinal section, not quite attaining the center of the conch in the apical portion, The shell expands from 4 mm. and 5 mm. to 5 mm, and 6 mm. in the 10 mm. of the phragmo- cone as measured ventrally. Expansion is continued in the 30 mm. of the living chamber to 15 mm. vertically and 12 mm. hor- izontally. The maximum length of the living chamber, which is incomplete adorally, is 45 mm. The adoral diameters are es- timated at 18 mm. and 16 mm.
The camere, of which eleven are preserved in the phragmo- cone, are very shallow, six occurring in a length of 3 name line septum is slightly greater than the depth of the camera in vertical curvature, and is only slightly curved horizontally. Evidently the sutures must have shown faint lateral lobes. The siphuncle is minute, less than .2 mm. in diameter, and separted by about its own diameter from the venter. The necks are short, the rings thin. The segments are not clearly outlined in the holotype, be- ing obscured by some dark calcite, but appear to present sub- orthochoanitic rather than cylindrical outlines.
Discussion.—The siphuncle lies very close to the venter in a stage closely approximating the apex of this species. It seems highly unlikely that it could become central in the apical chamber. The species can be distinguished from most other Chazyan forms by the generic characters. Fragments of a similar form, too incomplete for description and too poor to merit illustration, suggest the presence of a larger related species in the Chazyan.
A second specimen, retaining the adapical end of the shell, ap- pears to agree sufficiently with the holotype to be referred to this species. The apical chamber has a vertical height of 3 mm. from dorsum to venter. It is 1.2 mm. deep, while the following camera is only .6 mm. deep. Unfortunately the section does not show the siphuncle in this camera, but it lies close to the venter in im- mediately succeeding camerz and it seems highly unlikely that it will move toward the center appreciably in the small distance
75 ACTINOSIPHONATE CEPHALOPODS: FLOWER 75
remaining. This is of interest in view of the obvious stenosipho- nate and ellipochoanitic nature of the siphuncle wall, and in view of Kobayashi’s hypothesis (1937, p. 20) according to which such a species should have a siphuncle which is central in the initial part of the shell.
The species is represented in our collections by three speci- mens and some additional fragments.
Types.—Holotype and four paratypes, University of Cincin- nati Museum, Nos. 24181—24185.
Occurrence.—From the Valcour limestone, upper Chazyan, of Little Monty Bay, near Chazy, New York.
Genus CENTROCYRTOCERAS Foerste
Genotype.—Cyrtoceras subannulatum d’Orbigny (==Cyrtoceras annu- latum Hall). Trenton limestone of New York.
Centrocyrtoceras Foerste, 1926, Denison Univ. Bull., Sci. Lab. Jour., vol. 21, p. 366, pl. 43, fig. 5; pl. 45, fig. 4A-C; 1933, ibid., vol. 28, p. 45; 1935, tbid., vol. 30, p. 27.
Conch cyrtoconic, possibly gyroceraconic in some species, sub- circular in section. Sutures straight and transverse; siphuncle subcentral, composed of cylindrical or subcylindrical segments. Surface marked with transverse annuli which slope slightly api- cad on the venter, and with finer liree and striae which are trans- verse and follow the same course.
Discussion.—VThe species which have previously been placed within the genus range from the Stones River through the Tren- ton of New York. Except for one species, C. rotundum Foerste of the Prosser of Iowa, the genus is confined, so far as is known at present to the east. The single species known from the Chazy limestone is atypical in its compressed form, the position of the siphuncle dorsad of the center as well as by its minute size. The characters do not seem to warrant setting the species apart in a distinct genus.
Centrocyrteceras mozslai Flower, n. sp. Plate 5, fig. 8 Conch minute, gently curved exogastrically, The type, the
only specimen so far encountered, is 9 mm, in length and ex-
76 BULLETIN 109 76
pands from 1.6 mm. and 1.9 mm. to 2.5 mm. and 2.6 mm., the section being slightly compressed, Sutures transverse to the axis of the conch and straight. Depth of camera not observed. The adoral 5 mm, of the specimen apparently represents a living chamber; the adapical 4 mm. is without clear septa, although one is exposed where the specimen is broken at the base of the living chamber. The siphuncle lies halfway between the center and the dorsal side. Ornamentation consists of transverse an- nuli which are distant, rounded, thickened slightly dorso-later- ally, and are inclined very slightly apicad over the entire ventral surface.
Discussion.—The single minute specimen upon which the above description is based is not suitable for sectioning. The affinities of the species with Centrocyrtoceras is based upon the external form. The curvature is such that it cannot be consid- ered an immature portion of a Barrandeoceras, which would be much more gradually curved, judging from the very large umbili- cal perforation. The species is unique in its slightly compressed form, the siphuncle dorsad of the center, and in the subtubercu- late condition of the annuli dorso-laterally.
Type.—Holotype, University of Cincinnati Museum, No. 24188.
Occurrence.—Valcour limestone of Little Monty Bay, near Chazy, Clinton County, New York.
Genus TROCHOLITES Conrad
This genus, based upon Trocholites ammonius Conrad of the Trenton limestone of New York, was erected for coiled forms which expand gradually and consist of several volutions. The sec- tion is broadly rounded, and the siphuncle lies close to the dorsum. Hyatt (1894, p. 480) erected the genus Trocholitoceras for Can- adian species which differ from Trocholites mainly in the more compressed form of the later volutions, and in the early stages of the shell, which differ from Trocholites in having = slightly wider umbilical perforation, but mainly in the position of the siphuncle, which does not attain a position close to the dorsum
th ACTINOSIPHONATE CEPHALOPODS: FLOWER 77
until after the completion of the first whorl. The species previ- ously placed in Trocholites range from the Beekmantown (Ft. Cassin) to the Richmond, However, the Beekmantown Trocho- lites internastriatus has been removed to another genus, Curto- ceras, Ulrich, Foerste, Miller and Furnish. No species have pre- viously been known from the Chazyan, and the genus is yet to be recognized in the Black River. In the Trenton ib 1S) Lepre- sented by several species: the genotype from New York, Trocho- lites ammonius, T. canadensis Hyatt from Montreal, and 7. fabert Foerste from the Cynthiana limestone of Kentucky. Three Up- per Ordovician species from Cincinnati have been described in terms of this genus, 7. dyeri Hyatt from the Cincinnatian, T. minusculus Miller and Dyer from the Eden, and T. circularis Miller and Dyer which may be upper Maysville (Bassler, 1915, p. 1298) or Waynesville. T. planorbiformis occupies the Upper Ordovician of New York. This is a typical Trocholites. The species from Cincinnati are little known, and even their generic position is uncertain.
The two Chazyan species described below are of some inter- est in view of the problem raised by the writer (Flower, 1941) of the relationship between Canadian and Champlainian coiled cephalopods. Hyatt had assumed that the coiled Canadian and Champlainian species were not strikingly distinct from one an- other, and that the Trocholitide in particular represent a closely knit genetic group passing from Canadian to Champlainian and even Cincinnatian. The writer found in differences of the siphuncle wall evidence suggesting that two unrelated genetic stocks might be involved, although the similarities were so strong between some of these genera that it was recognized that the possibility must be considered that similar and contemporaneous changes might have occured in the Trocholitide and in the Tarphycera- tide, Deltoceratide and Plectoceratide. Subsequently more data on the structure of Canadian coiled cephalopods have been pub- lished by Ulrich, Foerste, Miller and Furnish, without, how- ever, any recognition of this problem, and indeed without any discussion of Hyatt’s views on phylogeny of these forms which
BULLETIN 109 78
“ 10/0)
were based upon a very careful comparison of the species with special reference to the early ontogenetic stages. Their illustra- tions show that in every case in which thin sections have been made and illustrated in Canadian coiled cephalopods, the con- necting ring is thick. In some cases this is interpreted as a de- pesit within the siphuncle. Deposits growing from the outer cameral surface of the ring are interpreted as cameral deposits. While correct enough from the point of view that they are formed outside of the original connecting ring, such an interpretation ignores the very obvious differences in structure and probably in composition of these deposits from aragonitic mantle secretions such as true cameral deposits. Only in one case, lVichitoceras Cecipiens (1942, p. 85) are thin connecting rings shown, It is not certain that this was drawn from a thin section.
At the time when the writer first pointed out the structural dif- ferences in the connecting rings of Champlainian and Canadian coiled cephalopods, no thin sections of any of the Trocholitidee were available for study. It now appears that a division o¢curs in genera assigned to this family similar to that noted in the coiled cephalopods with central or ventral siphuncles assigned currently to the Tarphyceratide, Deltoceratidz and Plectoceratide. The Canadian Curtoceras has complex rings, as shown by the illustra- tions of Ulrich and his associates. Data are not supplied for other genera in that work. The Chazyan Trocholites ruede- manni has thin structureless connecting rings, in which they agree with other post-Canadian cephalopods thus far studied. How- ever, according to Hyatt, there was a very close relationship be- tween Trocholites and Trocholitoceras. The Chazyan species of Trocholites are typical of this genus in the dorsal positions of the siphuncle from the earliest known growth stages, but in sec- tion 7. gracilis particularly approaches Trocholitoceras. Whether this resemblance is significant cannot be determined until the siphuncular structure of Trocholitoceras is made known.
Strand (1843) has figured thick rings in Discoceras and Schroederoceras which suggest that these Upper Ordo-
79 ACTINOSIPHONATE CEPHALOPODS: FLOWER 79
vician types may be directly descended from some such Can- adian ancestor as Curtoceras, but apparently differ strongly in this respect from at least Trocholites.
Trocholites ruedemanni Flower, n. sp. Plate 5, figs. 6, 7
This is a small species with rather broad rounded whorls. The phragmocone of the holotype includes about five and a half whorls and represents a mature or nearly mature specimen, The great- est diameter is 28.5 mm. which is taken before the completion of the fifth whorl as the remainder of the shell is incomplete. The section is depressed throughout. The earliest known portion is a broadly depressed oval in section, with no true impressed zone. Half a volution farther, the venter is broadly rounded, but the dorsum is straight and transverse, the sides strongly rounded. Farther orad an impressed zone develops, which in the outer whorls becomes half the height of the whorl. The venter is broadly rounded, the sides more strongly rounded, with the great- est curvature at the umbilical shoulders. The following dimen- sions taken at intervals of a half whorl will show the proportions and the habit of growth:
Width Whorl height Front venter to impressed zone 2.4 8 8 2.8 1.0 1.0 3. 1.5 1.4 3.9 2.9 1.6 4.5 3.2 2.0 6.5 4.0 2.5 9.0 5.0 5.8 11.0 6.0 4.0 14.0 9.0 5.8
The sutures bear shallow lateral lobes, umbilical and ventro- lateral saddles, and a faint ventral lobe in the mature whorl. The impressed zone is marked by a deep lobe, so that a cross section of the shell shows the plane of the suture as oblique. The septa are evenly curved, and are less than one camera in depth. Four camere occur along the venter in a length equal to an adoral diameter of 9 mm.
The siphuncle is cylindrical, small, and in contact with the dorsal wall except in the first half whorl, where it is nearly three
80 BULLETIN 109 80
times as far from the venter as from the dorsum, In the last whorl the siphuncle is about .£8 mm. in diameter. It is ortho- choanitic with very short straight septal necks which scarcely complete the turn so that they lie parallel to the shell axis. The connecting rings are thin and show no differentiation of struc- ture.
Only a portion of the living chamber is known. It describes one quarter of a volution and shows indication of being geron- tically uncoiled adorally, the dorsum coming to be slightly sep- arated from the earlier whorl.
The surface of the shell, though poorly preserved, shows traces of transverse markings. On the last two whorls there are small rounded nodes on the umbilical shoulders, about eight on the last half volution of the holotype. Ventrad of these are faint traces of costa which slope apicad as they approach the venter, and apparently fade out before attaining the broad ventral zone.
Discussion.—This species is represented by a single complete specimen, but there are numerous fragments, indicating that the species 1s not uncommon in the Valcour limestone, and that its small size, indicated by the type, is uniform. In coiling it is in some respects more similar to Trocholitoceras as than to Trocho- lites. As might be expected if the two genera are related, as is indicated by the form though not by the internal structure, this species is intermediate between Middle Ordovician Trocholites so far studied and the Beekmantown Trocholitoceras in the po- sition of the siphuncle in the early stage of the shell.
The species can be readily distinguished by its small size, broad whorl, and the presence of nodes on the umbilical shoulders. From the associated 7. gracilis it may be distinguished by the broader more rounded whorls, the greater dimensions of the whorls in specimens comparable in the diameter of the disc, and the more involute condition.
Holotype.—University of Cincinnati Museum, No. 24193.
Occurrence——Valcour limestone, upper Chazy, Little Monty Bay, southeast of Chazy, New York.
81 ACTINOSIPHONATE CEFHALOPODS: TLOWER 81
Trocholites gracilis Flower, n. sp. Plate 5, figs. 4, 5
This is a small shell, the maximum disc known being 24 mm. but differs from 7. ruwedemanni in the narrower whorls, the arched venter in the mature shell, the looser coil, and the absence of lateral nodes on the shell. The species is known from two fairly complete specimens as well as a number of fragments. The holotype, the most complete shell known, fails to retain the sur- face of the lateral portions of the early whorls. Fortunately this information is supplied by a paratype. The umbilical perfora- tion is very small, and the shell is in contact at the first volution. The impressed zone begins early as in 7. ruedemanni but is never so deep as in that species. The early whorls are circular or nearly so except for the development of the impressed zone. Farther orad the greatest width comes to lie dorsad of the cen- ter of the shell though the venter is still slightly flattened though narrow. In the last volution the venter becomes more elevated and develops an obscure keel. Here the whorl is 6.5 mm. broad and 7 mm. high. The preceding whorl is 6 mm. broad and 5 mm. high.
The sutures lack clearly defined lobation, but slope adapically toward the venter. Three camere occur in a length on the ven- ter equal to an adoral diameter of 5.5 mm. The siphuncle is orthochoanitic and similar to that of 7. ruwedemanm. From the third whorl it is in contact with the dorsum. Its position in earlier whorls is unknown. The last half whorl of the paratype consists of a living chamber which is apparently complete adoral- ly. The surface of the shell is marked by rugose lines of growth which slope apicad toward the venter. The internal mold shows traces of these markings in the form of obscure lateral coste.
Discussion.—This species is presumably considerably rarer than T. ruedemanni. Calcite filled specimens have proved diffi- cult to extract as the limestone matrix is harder than the calcite and ordinarily specimens lack the lateral portion of the inner whorls. However, the paratype shows an almost undamaged lateral surface. The species may be readily distinguished from
82 BULLETIN 109 82
T. ruecemanni by the narrower whorl, the elevated venter in the | mature part of the shell, and the different habit of growth. The whorls are much narrower than in that species, and although it was not pessible to study the species by cross sections, the im- pressed zone was evidently shallower. In the small size and nar- rowly elevated venter, no younger forms are comparable.
Types.—Holotype and paratype, University of Cincinnati Mu- seum, Nos. 24191-24192.
Occurrence.—From the Valcour limestone, upper Chazy, from Little Monty Bay, southeast of Chazy, N. Y.
REFERENCES
Bassler, R. S. 1915. Bibliographic index of American Ordovician and Silurian Fossils. U. S. National Museum, Bull. 92, 2 vols., 1521 pp. Flower, R. H. 1941. Notes on structure and phylogeny of eurysiphonate cephalopods. Paleontographica Americana, vol. 3, No. 13, 56 pp., 3 pls., 3 figs. Foerste, A. F. and Teichert, C. 1930. The actinoceroids of east-central North America. Denison Univ. Bull., Sci. Lab., Jour., vol. 25, pp. 201-296, pls. 27-59. Kobayashi, T. 1937. Contributions to the study of the apical end of the Ordovician nautiloid. Japanese Jour. Geol., Geogr., vol. 14, pp. 1-22, pls. 1-2. Ruedemann, R. 1906. Cephalopoda of the Champlain basin. New York State Museum, Bull. 90, 611 pp., 38 pls., 57 text figs. : Ulrich, FE. O., Foerste, A. F., Miller, A. K. and Furnish, W. M. 1942. Ozarkian and Canadian cephalopods. Part I: Nautilicones. Geol. Soc. Amer., Special Papers, No. 37. 157 pp., 57 pls.
$3 ACTINOSIPHONATE CEPHALOPODS: FLOWER 83
Vie sOMEa SUR TAN CY REOCONIC CEPHALOPODS FROM INDIANA WITH NOTES ON STRATIGRAPHIC PROBLEMS
ABSTRACT
Three new species and one new genus of cyrtoconic Silurian cephalopods from Indiana are described, with remarks on the occurrence and current problems of correlation. The new species are Pentameroceras cumingsi, Tetrameroceras faberi, and Laureloceras cumingsi, the last being also a new genus.
INTRODUCTION
In the following pages long standing descriptions of a few cyrt- oconic cephalopods of more than usual interest are brought to- gether. Tetrameroceras faberi of the Osgood limestone is sig- nificant as the first record in America of this genus, which is pro- lifically developed in the Silurian of Bohemia. Pentameroceras has long been known to occur in the Silurian of northern Indiana, but has been identified in terms of the single Bohemian species. Restudy of this form shows that it is distinct from those which Barrande included under his name, and which apparently con- stitute in themselves several distinct species. Both of these genera are perhaps better known from the European Silurian. The third form discussed, Lauwreloceras cumingsi, represents one of three species of the new genus Laureloceras which is known only from the Laurel limestone.
SILURIAN CEPHALOPOD FAUNAS IN INDIANA
Little is known concerning the cephalopods of the Osgood limestone, a relatively barren formation, Foerste has illustrated a Dawsonoceras americanum from it, which seems to be the only previous record of an Osgood cephalopod prior to the present description of Tetrameroceras faberi.
The overlying Laurel limestone contains a prolific cephalopod fauna but one which is generally widely scattered and quite sparsely distributed. One locality, two miles east of Westport, Indiana, has yielded a profusion of cephalopod shells from a sin-
S4 BULLETIN 109 84
gle layer. This association has been found to contain a number of undescribed or recently described species many of which are not known from the rest of the Laurel, This lens has yielded the
following species:
Harrisoceras reevesi Flower
Harrisoceras, i. sp.
Virgoceras cancellatum Flower
Protokionoceras, n. sp.
Leurocycloceras bucheri Flower
Dawsonoceras americanum (Foord)*
Dawsonoceras, i. sp.
Laureloceras cuminsgt Flower, n. sp.
Ormocerds, i. sp.*
Elrodoceras indianense (Miller) *
Elrodoceras, n. sp.
Those marked with an asterisk are known from other locali- ties in the Laurel not consisting of any marked concentration of cephalopods. Although the shells in this bed show a dominantly parallel arrangement, it is not regarded as an association of dead shells. Rather, the parallel arrangement of shells is due to re- working of the upper part at least of the bed after an initial period of deposition. This is shown clearly by the fact that some shells have been broken irregularly across inorganic infilterated calcite which can be explained by supposing that the shells were initial- ly buried, the cavities of the shell filled in with inorganic material. Then reworking of the sediment caused these shells to not only be uncovered and moved, but also broken. <A similar phenome- non has been found in the Valcour limestone of the Chazyan, and may be much more widespread than has previously been supposed. Indeed, it may prove that many of the limestones which have been noted for cephalopod shells lying in parallel di- rections represent such phenomenon. If so, much that has been written about these beds, which have been regarded as contain- ing an association of dead shells washed together by chance, perhaps far from their normal environments, will have to be re- jected.
Another line of reasoning also suggests strongly that the asso- ciation is a natural ecological one. In association with the
85 INDIANA CYRTOCONIC CEPHALOPODS: FLOWER 85
cephalopods in this bed were found few brachiopods, an Atrypa and a Cyrtina, but a great profusion of trilobites, largely Dalman- ites, sensu lato, and Bumastus. Also there were a considerable though smaller number of gastropods, and a profusion of echino- derm remains, largely unidentifiable, but certainly containing some forms identifiable as cystidians. The association of cepha- lopods, trilobites and gastropods in abundance in hard limestones is a phenomenon so widely distributed in the Paleozoic that is is obviously a natural association. It has been dealt with else- where as the cephalopod facies.*
The generalized cephalopod fauna of the Laurel contains spe- cies for the most part distinct from those found in the lens at Westport, but the same genera are involved. The species to the writer, some undescribed, are included in the list :
Harrisoceras laurelense Flower Leurocycloceras franklinense (Miller) Dawsonoceras americanum (Foord) Protokionocerds, nu. sp.
Ormoceras, 1. sp.
Elrodoceras indianense (Miller) Laureloceras howardi (Miller) Laureloceras nashvillense (Miller) (Not known in Indiana) Heracloceras elrodi (White) + Heracloceras abruptum (Hall) “*Nautilus’’ oceanus Hall
The Laurel fauna is one dominantly of orthoceracones, as can be seen from the above list. | Phragmoceroid shells and _ brevi-
* Flower, R. H.: Environment of carly Paleozoic nautiloids, Nat. Res.
Council, Rept. committee on marine geology as related to Paleontology, 1941-42, pp. 37-40.
{t This and the following species are probably not actually Heracloceras Teichert, a new name proposed for Gigantoceras Hyatt which was preoe- eupied. The genotype of Gigantoceras is Gyroceras inelegans Meek of the Middle Devonian. The Silurian species can be distinguished on the basis of lateral lobes of the sutures, but both Devonian and Silurian spe- cies are so little known that further division of this genus does not seem advisable at the present time. Silurian species are probably closely related to Uranoceras. The relationship of the single described Devonian species is uncertain, but it is suspected that it may be a compressed derivative of the Khadinoceratide.
386 BuLLETIN 109 86
cones are unknown, and the only curved and coiled genera are Laureloceras and Heracloceras, though a third genus may have to be added for the reception of Nautilus oceanus Hall when that species is made better known from additional material. At pres- ent it is known only from the type.
The overlying Waldron shale has yielded few cephalopods. There is a smooth orthoceracone, Orthoceras stimulator, of un- known structure and therefore uncertain taxonomic position. Dawsonoceras, more abundant in the Waldron of Tennessee than in Indiana, shows wide variation in surface features, and probably more than one form is involved (Flower, 1942). The only other Waldron cephalopod is Lechritrochoceras waldronense Hall. Orthoceras amycus Hall is a little known annulated species pos- sibly from the Waldron, the generic position of which is uncer- tain.
The overlying Louisville limestone is relatively barren of cephalopods in Indiana. Doubtfully reported from it is Harriso- ceras ignotum Flower (1939). This species was found by the writer in the summer of 1941 in Silurian limestones rich in cepha- lopods near Olive Hill, Tennessee at the southern end of the Se- quatchie anticline. The associated species were not conspecific with any known from the Laurel of Indiana.
Correlation of the Silurian of southern Indiana and northern Indiana has been complicated by an intervening area covered by drift in which no exposures are available. The lowermost of the exposed Silurian beds of northern Indiana, the Missinewa shale is correlated with the Osgood by Cumings and others. It has yielded only a few flattened orthoceracones, mostly undeter- minable species of Protokionoceras. The Liston Creek limestone, regarded as the probable equivalent of the upper Clinton beds of southern Indiana and Tennessee, including the Laurel to the Louisville and probably also overlying formations, and of the Manistique in the north, has a large but mainly undescribed cephalopod fauna. Orthoceracones are abundant, and though many of the Laurel genera reappear none of the Laurel species
87 INDIANA CyrTOocoONIC CEFHALOPODS: FLOWER 87
are duplicated. The following list indicates the affinities of many of the undescribed species.
Harrisoceras obstructum (Newell) Harrisoceras monocameratum Flower Protokionoceras, sp., aff. P. myrice (Hall) Kionoceras ef. scammondi (McChesney ) Kionoceras ef. stria (Hall and Whitfield) Leurocycloceras, Nn. sp.
Leurocycloceras ef. niagarense (Hall) Armenocerds, 1. Sp.
Bickmorites bickmoreanum (Whitfield) Bickmorites muarshi (Hall) Oxygonioceras wabashense Foerste Phragmoceras angustum (Newell) Phragmoceras projectum (Newell) Tubiferoceras lineare (Newell) Tubiferoceras gilberti (Kindle and Breger) Gomphoceras, sp.
Hexameroceras, sp.
Lechritrochoceras, sp.
It is believed that the orthoceracones, from their widespread occurrence in the Silurian of southern Indiana and Tennessee, were indigenous to this area, while the phragmoceroids repre- sent a faunal incursion, probably from the north. If this is so, the Liston Creek limestone might be expected to show some zonation of the fossils, and the phragmoceroids might be expect- ed to put in a relatively late appearance. However, at two lo- calities at which it was possible to determine the relative posi- tion of the various species in the beds, it was found that the phragmoceroids and the Oxygomioceras occurred low in the sec- tion, somewhat below the bed which has yielded the great pro- fusion of orthoceracones, many of which show Laurel affinities.
The Huntington limestone cephalopod fauna is very inade- quately known, There can be little question, however, but what it is a typical Racine association, and the first of the Silurian fau- nas of Indiana which can be placed in the Lockport, using the term in its broader sense, as the upper of the two major divi- sions of the American Middle Silurian. Its large orthoceracones are clearly in a large part identical with those of the Racine, and some species are involved which seem to have escaped descrip- tion thus far. Kionoceroids are abundant and essentially Racine
88 BuLueTiIn 109 88
in affinities. Some of these species may appear in the Liston Creek dolomite, Dazwsonoceras occurs here, and includes types similar to modocostatum and grant. Phragmoceras attains a greater abundance and variation in size than in the Liston Creek, and one of the largest Hexameroceras, H. cacabiforme (Newell) occurs here. Mandaloceras wabashense (Newell) and Penta- meroceras cumingsi Flower, n. sp. represent the appearance of genera new to this region. Lechritrochoceras desplainense (Mc- Chesney), a Racine species, occurs here in abundance. The genus is one found in the Clinton, being present both in the Waldron shale of Indiana and the Irondequoit limestone of New York (Flower, 1942). The brevicones of depressed section, Amphi- cyrtoceras and |Worthenoceras which characterize the Racine and Cedarville are not yet known from northern Indiana, nor are Cyrtorizoceras or other of the numerous cyrtocone genera of the Racine and Port Byron faunas.
In general, it appears from their prolific development in the east central area, that either, most of the large orthoceraconic types characteristic of the earlier part of the Middle Silurian must have developed here indigenously, while in contrast, two dis- tinct northern faunas developed. One is an early one, found in formations of Clinton age, and characterized above all else by Discosorus and its allies. This fauna is an arctic one, and only a few stray members of the Discosoride passed south of the northern Michigan region, Kayoceras appearing in the Hopkin- ton of Iowa, and Discosorus itself penetrating the New York Clinton. Wherever in the series of northern Silurian outliers this horizon is capped by another it is very likely to be a bioherm association in which breviconic cephalopods are conspicuous, and orthoconic types are absent. It is from this direction that most of the breviconic genera common to the American and European Silurian entered, for the most part. IJnversoceras, Pentamero- ceras, Mandaloceras, Phragmoceras, Hexameroceras, Cyrtori- zoceras and many other cyrtoconic and breviconic genera appar- ently mark this invaison. Some of these penetrate Indiana in
“ ithaca as
89 INDIANA CYRTOCONIC CEPHALOPODS: FLOWER 89
pre-Racine time, as they clearly occur in the Liston Creek lime- stone, but failed to penetrate farther south into the Laurel. Possi- bly the Cincinnati-Chicago axis was an important barrier at this time, as was the contemporaneous Cattaract axis of Ontario. However, as there is no evidence that this axis was a definite barrier to deposition, it is more likely that climatic and environ- mental factors harder to reconstruct may have been the deter- mining factors.
If the Liston Creek limestone derived some of its exotic ele- ments, such as Phragmoceras, Tubiferoceras and Gomphoceras from an arctic invasion, it must be at least in part younger than the beds carrying the Discosorus fauna, and may be equivalent of the Attawapiskat limestone and related formations. Further, if the Liston Creek is, as is now coming to be accepted, Clinton in age, the Discosorus faunas must be relatively early Clinton. This is consistent with the known facts, for Discosorus itself penetrates the New York Clinton only in the relatively early Reynales limestone; the related Kayoceras invades the Hopkin- ton, the lowermost Middle Silurian formation of Iowa. In Anti- costi the discosorids are best developed in the lowermost of the Silurian formations, the Gun River, where they are joined by a few orthoceracones Kionoceras bellatulum, Ormoceras morrist, and Spyroceras tenuiclathratum which are faintly reminiscent of the orthoceraconic fauna of the east central interior.
Genus PENTAMEROCERAS Hyatt Genotype.—Gomphoceras mirum Barrande.
Conch erect, breviconic, the shell closing over the adoral end in a domelike manner, leaving for an aperture a long hyponomie sinus, and five shorter sinuses which radiate from a central point.
The shell is erect, and shows no clear traces of either exogastric or endogastric origin. The sutures are straight and transverse, the siphuncle is ventral, marginal, and is composed of elongate- oval rather slender segments which are free from any trace of organic deposits,
90 BuLLETIN 109 90
In section the genus is variable, being sometimes compressed, sometimes depressed, and again circular in section.
Unfortunately some confusion attends the use of Pentameroc- eras mirum as a genotype, inasmuch as Barrande included two and possibly three species under that name. To eliminate this difficulty it is necessary to select a type for the species. In making this selection, the original of Barrande’s figures 10 to 14 on plate 91 are selected. This selection is made rather than us- ing the first specimen to be figured, because it is much _ better known and much more adequately illustrated. Not only are all necessary views of the specimen shown, but the phragmocone has been sectioned to reveal the outline of the segments of the siphuncle.
The new name Pentameroceras depressum is here proposed for the original of Barrande’s figures shown on plate 82, figures 20-25. In this species the section is markedly depressed, the dorsal sinus is shorter and slightly broader than any of the others. Barrande also included in Gomphoceras mirum a_ diminutive specimen illustrated on his plate 82, figures 17-20. This specimen is differentiated from the others readily by its small size. No apertural view is shown, and the details of the aperture are un- known. There is no certainty from his figures whether the section is compressed, depressed or circular. Without these data it seems unwise to propose a name for this specimen.
In placing individuals embracing a wide size range within a single species, Barrande seems to have been accepting the belief later expressed by Hyatt, that many brevicones attained a perfect contracted aperture in immature individuals, which was resorbed periodically in growth. An alternate explanation is that maturity was attained within a species over a remarkable size range. This apples today in certain gastropod species which attain peculiar
apertural features upon maturity, Still a third explanation which
must be considered is the possibility of sexual dimorphism. The problems attending the recognition of such dimorphism in extinct organisms, such as the brevicones, have been discussed by Flower
91 INDIANA CyrTOCONIC CEPHALOPODS: FLOWER 91
(1939, p. 7) and Teichert (1940, p. 60) and were first suggested by Ruedemann (1921, p. 317). Possibly this tiny specimen figured by Barrande might be a diminutive male of one of the other species. If so, sexual dimorphism is here responsible for consid- erable difference in size as was suggested by Ruedemann and by Teichert, instead of the relatively slight differences attributed to this cause by the writer. The two are not mutually exculsive.
In the opinion of the writer, the more conservative course in a situation of this kind, is the proposal of distinct specific names for the two specimens, which might be sexual variations of the same species. To include both under a single name should re- quire a definite knowledge which can never be obtained for an extinct organism and is justified only in such peculiar cases as that noted by Ruedemann in first proposing the application of sexual dimorphism to breviconic cephalopods. Ruedemann found a large number of specimens in association within which two size groups could be discerned. It does not seem advisable in dealing only with two or three specimens, as in the present in- stance, to attempt any conclusions of this sort.
Pentameroceras has been recognized in the Middle Silurian of America, but no very critical study has been made of the forms with the view of determining specific boundaries and differences. Foerste (1930, p. 380) noted the presence of Pentameroceras in the Racine dolomite at Milwaukee and Wauwatosa, in the equiv- alent Huntington dolomite at Delphi, Indiana, and the Peebles dolomite, of Guelph age, of Ohio. He illustrated the Peebles specimen under the name of Pentameroceras cf. mirum (Bar- rande) and considered that “it is not likely that the Bohemian species succeeded in migrating as far as the central states without recognizable changes, but no special attempt has been made as yet to discriminate the different forms.’ He pointed out certain differences between the Pohemian forms, but stated that the spec- imen from Peebles was too incomplete to serve as a type.
The differences cited by Foerste consist of the following fea- fmes 2 (1) a shorter body chamber (2) a less erect form (3) a compressed rather than a depressed section. In noting the last
BuLuEeTIN 109 92
Ne) bo
varence Foerste had in mind the specimen figured by Barrande _- which the name Pentameroceras depressum is here proposed. The other differences, however, serve very well to distinguish this form from the type here selected. In addition, the lectotype of Pentameroceras mirum has a long living chamber in which the the greatest diameters are attained considerably above the base, and the contraction from the point of greatest diameter to the aperture is much more gradual than in any known American species.
The differences between the Peebles specimen and the one from Port Byron, Hlinois, which Foerste subsequently named Pen- tameroceras byronense (Foerste 1930, p. 117, pl. 23, figs. 5A-C,6) are less evident. In both the five lobes of the dorsal part of the aperture are relatively short and broad, and are rounded lobes rather than linear slits. The Peebles specimen is inflated at the base of the living chamber and contracts gradually to the aperture, the convex sides converging slowly but uniformly. In the Port Byron specimens the conch expands to a point two-thirds the distance from the base of the living chamber to the aperture, and then contracts more abruptly orad. The differences seem to be sufficient to warrant considering the Peebles and the Port Byron forms as distinct species, though the two Port Byron specimens figured by Foerste suggests that a larger series might show more gradation between these two forms. Possibly in the development of broad rounded lobes instead of slitlike apertures, there are features which may indicate a close relationship between these two forms, both of Guelph age, and which might be explained as apertural imperfections in the last phylogerontic members of Pen- tameroceras. ‘This hypothesis will require further investigation, however. Evidence is meagre, and the possibility remains that in the few Guelph specimens known, the aperture may not have been
‘etely formed. This explanation is probably not the true e internal molds of the Port Byron specimens show argination of the vertical outline and a slight flaring of
93 INDIANA CYRTOLSONIC CKPHALOPODS ; FLOWER 93
the aperture beyond, which indicate a thickening of the interior of the shell around the aperture found only in fully developed geron- tic individuals. The development of the basal zone is another indication of this stage of growth (Foerste 1930, pl. 23, fig. 5B).
Two other specimens of Pentameroceras from the Silurian of Hudson Bay have been figured. The precise horizon of both is uncertain. They came either from the Ekwan or the Attawapis- kat limestones, of which the former underlies the latter. Pen- tameroceras rarum Parks (see Foerste and Savage, 1927, p. 102, pl. 23, fig. 7A-C) is the only Pentameroceras known which is clearly exogastric in its affinities, as is Mandaloceras for the most part. The five rays of the dorsal aperture are slitlike, sub- equal in length, the hyponomic sinus is long, straight when seen in vertical section instead of curved with the convexity orad as in all other known species, and the section of the shell is faintly compressed. Pentameroceras (?), sp. (Foerste and Savage, p. 103, pl. 23, fig. 6A-C) is a minute specimen, recalling in vertical outline the Peebles specimen, but with five lobes of the dorsal part of the aperture rounded, very poorly developed, and surrounding a wide circular space. The section is faintly compressed, and is more narrowed ventrally than dorsally.
Pentamercceras cumingsi Flower, n. sp. Plate 2, figs. 1-3
(?) Pentameroceras mirum Newell, 1888, Proc. Boston Soc. Nat. Hist., vol. 23, p. 483.
Conch erect, small, breviconic, but with the earlier portion ex- panding very gradually, attaining the point of gibbosity slightly above the middle of the mature living chamber, from which the shell contracts rapidly over the apertural end leaving only the restricted lobate aperture characteristic of the genus. The venter appears faintly concave in the early part of the shell, becoming straight over the base of the living chamber. The dorsum is straight to the point at which convexity appears. The section is circular. The conch expands in the holotype from a diameter of
94 BuLLETIN 109 94
7 mm. at the base of the specimen, increasing in a length of 17 mm. to 12 mm. The aperture closes over the adoral end at a length of 23 mm.
The type preserves seven camere in a length of 10 mm., the last camera subequal to the preceding in length. The siphuncle iS not exposed on the basal septum of the specimen,
The hyponomic sinus, 8 mm. in length, is inflated at its tip, but narrow basally. The five arms of the main part of the aperture about 6 mm. in length, are likewise slightly inflated at their tips. The median lobe is slightly broader than the others. When viewed laterally, the hyponomic sinus presents a slightly curved outline, the convexity being directed orad. The surface of the shell is not preserved.
Discussion—The type upon which this species is based 1s from the same locality as the specimens which Newell (1888) identified as Pentameroceras mirum. It is not possible to tell from Newell’s brief description whether or not his forms were conspecific with this one, as seems highly likely. P. cwmingsi is the only Pentameroceras so far known in which the section is circular in the mature state. It is differentiated from the com- pressed P. mirum, P. rarum, P. byronense and the Peebles spec- imen attributed to P. cf. mirum by the compressed section common to all of those species. P. depressuwm is markedly depressed in section. In having slender slithke sinuses to the dorsal part of the aperture this species is allied to P. mirwm and the two Bo- hemian species, but is separated from the remaining American forms, including the Peebles specimen and the unnamed one from-Hudson Bay. From P. rarwm this form is distinguished by the circular section, the curved condition of the hyponomic sinus when viewed in vertical section, and the somewhat longer lat- eral sinuses. |
Type.—Holotype, University of Cincinnati Museum, No. 23095.
Occurrence.
From the Huntington dolomite, of Racine age, (Lockport), Middle Silurian, from Delphi, Indiana.
95 FINDIANA CYRTOCONIC CEPHALOPODS ; FLOWER 95
Genus TETRAMEROCERAS Hyatt, 1884
Genotype.—Phragmoceras bicinctum Barrande, 1867 Tetrameroceras Hyatt, 1884, Boston Soc. Nat. Hist., Proe., vol. 22, p. 277; Hyatt, 1900, Cephalopoda, in Zittel-Eastmann Textbook of Pal- contology, vol. 1, 1st ed, Pp. 612; Foerste, 1926, Denison Univ. Bull. Sei. Lab., Jour., vol. 21, p. 360, pl. HOeton Ace.
Shell compressed, phragmoceroid in aspect, the living cham- ber swollen and generally convex in both dorsal and ventral pro- fles. The venter, as marked by the hyponomic sinus and the siphuncle, 1s concave in the early stages and the dorsum con- vex. The genus is characterized mainly by the form of the aper- ture which develops a long hyponomic sinus and four smaller sinuses giving the main part of the aperture a quadrate aspect. The siphuncle is made up of convex segments which contain actinosiphonate deposits.
Discussion-—The first known American species of Tetramer- oceras is described below. Curiously this genus, which one might expect to appear in America in the latter half of Middle Silurian time, along with other genera which are common to the Middle Silurian of America and Bohemia, instead, appears in the Osgood limestone which is Clinton and probably relatively early Clinton. The following Bohemian species, all described by Barrande as members of the genus Phragmoceras, are properly placed in Tetrameroceras. All forms from the Middle Silurian, etage Bot Bohemia: T. rimosum, T. lovem, T. discrepans, T. insolitum, is vetus, T. problematicum, T. infaustum, T. deshayesi, T. bellatu- lum and T. bicinctum.
Tetrameroceras faberi Flower, n. sp. Plate 1, fie. 1; Plate 3; fis. 1
This species is represented in our collections by a single speci- men of a mature shell which is probably slightly compressed by pressure. The shell is 90 mm. in length and increases in height from 21 mm. at the base to 62 mm. slightly above the base of the living chamber. The dorsal outline is strongly and uniformly convex at the base of the specimen, having a radius of curvature of 80 mm. The curvature becomes stronger at the adoral part of the living chamber, its radius decreasing to 40 mm. The venter
BULLETIN 109 96
io) for)
is straight from the initial part of the known shell to the adoral portion of the living chamber, where it becomes slightly convex. The sutures develop slight lateral lobes adorally, but rise only slightly orad on the venter. The siphuncle is scalariform, close to the venter, and without any known deposits. The eleven pre- served camere of the phragmocone increase in depth from 3 mm. to 9 mm., the maximum depth being attained at the fifth camera before the living chamber. Beyond that point the camere grow progressively shorter. Traces of vestigial cameral deposits are found at the base of the specimen, but the surfaces fail to show circumferential lobation. They are strongest ventrally, absent dorsally, and form a groove of the internal mold parallel to the suture slightly orad of midheight of each camera. Were they not deeply incised and rather irregular, these markings might be interpreted as the adoral end of the mural part of the septum. The living chamber has a basal height of 60 mm., a width of 30 mm. The height increases to its maximum of 62 mm., one- third the distance to the aperture, while the width remains the same. Beyond this point the shell contracts vertically and hori- zontally to the aperture. The hyponomic sinus is 38 mm. long. and slightly inflated. The main aperture is marked by a pair of fingerlike lobes projecting obliquely dorsad, and a shorter more rounded pair projecting ventrad, The lateral pressure which has slightly distorted the shell has made these seem asymmetrical. Discussion.—This species is of interest in that while it is a relatively early appearance of this genus in the Middle Silurian, it fails to show features which are generalized. The endogastric condition of the apical part of the shell is not so marked as in many Bohemian species of Tetrameroceras, and the aperture is more strongly contracted than in many of these previously de- scribed species, where it is relatively open and the lobes are short and rather broadly rounded. In this species, however, the lobes are essentially linear slits, slightly rounded at the ends, and they
97 INDIANA CYRTOCONIC CEPHALOPODS. ; FLOWER 97
form the main part of the aperture of the shell. The form of the segments of the siphuncle is typical of the genus, but the apparent absence of actinosiphonate structure is not, This may be attrib- uted either to poor preservation or to the fact that the specimen has not attained a gerontic condition as is shown by the absence of a basal zone, and the absence of any trace of thickening of the shell near the aperture. Cameral deposits are, however, slightly feveloped, but can be discerned only in the apical part of the specimen.
Holotype.—University of Cincinnati Museum, No. 22532.
Occurrence.—From the Osgood limestone, Madison, Indiana. The Osgood is the lowermost formation of the Clinton of Indiana, overlying the Brassfield of Medinan, Lower Silurian age.
Genus LAURELOCERAS Flower, n. gen.
Genotype.—Laureloceras cumingsi Flower, n. sp.
Conch cyrtoconic or more probably gyroceraconic when com- plete, expanding very gradually, and slender. The section is a compressed oval, the venter considerably more narrowly rounded than the dorsum. The sutures are essentially transverse to the axis of the shell, and may or may not develop broad lobes over the lateral surfaces. The siphuncle is close to the venter. The septal necks are straight and orthochoanitic, the connecting ring somewhat expanded, No deposits are known in the interior.
This genus is erected for the reception of three species, the genotype, L. cumingsi, which is described and illustrated here, and the two previously described forms, L. howardi ( Miller, 1893, p20, pl. 12, iie,-1) of the Laurel’ limestone of Indiana, and L. nashvillense (Miller, 1891, p. 697, pl. 16, fig. 1), from the Laurel limestone of Tennessee.
Although very simple in external aspect, there are few de- scribed genera which are at all similar in aspect. Other com- pressed cyrtoconic smooth-shelled genera are largely cyrtochoa-
98 BULLETIN 109 98
itic. This applies to Oonoceras Hyatt and _ its allies including Richardsonoceras and Cyrtorizoceras. The only Ordovician genus at all simiar in aspect is Graciloceras Flower, described in an earlier paper in this series, but the aspect of the two genera is very distinct, Graciloceras being a cyrtocone, with a short phragmocone of very closely spaced septa. Silurian cyrtoconic cephalopods which resemble Laureloceras only remotely are cyrtochoanitic. No comparable younger forms are known,
Laureloceras cumingsi Flower, n. sp. Plate 5, figs: 9, 12
This species is based upon a single specimen which describes about three-eighths of a volution, in which the radius of curva- ture of the venter increases from 65 mm. to 117 mm. in a ventral length of 160 mm. and an actual length of 125 mm. The shell is compressed about uniformly throughout, the height being 27 mm. with the width of 20 mm. The venter is considerably more narrowly rounded than the dorsum. The height of the type increases in 100 mm. as measured on the venter from 21 mm. to 38 mm.
The sutures are nearly transverse, but slope slightly orad on the venter. The camerz are deep, four and a half in a length equal to an adoral shell height of 25 mm., and five in a length equal to an adoral shell height of 35 mm. The septum is normal in curvature, equal to the depth of a camera in vertical section, being 5 mm. deep at a shell height of 20 mm. The siphuncle is located about 1 mm. from the ventral wall. It is 1.2 mm. across the septal foramen and expands within the camerze to 2 mm. The septal necks are inclined parallel to the axis of the shell and are properly orthochoanitic. The connecting rings are convex in section. No organic deposits are noted in the siphuncle, The section illustrated has the structure somewhat complicated by adventitious pyrite.
The surface of the shell is not clearly preserved. Enough of the shell is preserved to indicate, however, that the surface must
have been essentially smooth. There is no indication of a
99 INDIANA CYRTOCONIC CEPHALOPODS ; FLOWER 99
hyponomic sinus, but it is not certain whether one was present or not.
Discussion.—This species is differentiated from Lawreloceras nashvillense (Miller, 1891, p. 697, pl. 16, fig. 1) by the somewhat closely spaced septa, five occurring in a length equal to the height of the shell in L. cumingsi, and only four in an even later stage of L. nashvillense. These two species are quite similar in curva- ture, L. nashvillense being perhaps slightly less coiled, and slightly less rapidly expanding. Although the siphuncle of that species is not known there can be little doubt but that it is congeneric with L. cumingsit which it resembles very strongly. This species, from the Laurel limestone of Nashville, Tennessee, appears to be known only from Miller’s original specimen and description.
Very similar also is Laureloceras howardi (Miller, 1893, p. 320, pilei2. ise 1) iron: the’ Laurel limestone of St. Paul, Indiana. This species is considerably more strongly curved than L. cum- tmgst and more rapidly expanding. The septa are more closely spaced and the sutures are evidently more inclined to the axis of the shell, sloping orad strongly on the venter. The lateral lobes shown in the holotype are probably not diagnostic but appear to be a phenomenon attendant upon the weathering of a lateral surface,
No other congeneric species are known. Members of the genus bear a superficial resemblance to the smooth-shelled genus Oxygonioceras Foerste of the Silurian, This genus is represent- ed in the Liston Creek limestone, of which the Laurel is partially equivalent, though the Liston Creek limestone is probably equiv- alent also to higher formations of the Silurian of southern Indiana and probably also of Tennessee, by Oxygonioceras wabashense Foerste. All known specimens of Oxygonioceras can fortunately be distinguished from Lawreloceras species by their much more closely spaced septa, a superficial but highly convenient criterion. Oxygomioceras differs from Laureloceras in the strongly cyrto- choanitic structure of the siphuncle, a fact which it has been pos-
100 ; BULLETIN 109 100
sible to confirm on the basis of O. wabashense of the Liston Creek limestone, as well as upon the basis of specimens and Barrande’s figures of Silurian species of Bohemia, and one species to be de- scribed elsewhere from the Silurian of Arisiag, Nova Scotia.
Type.—Holotype, University of Cincinnati Museum, No. 24194.
Occurrence.—From the Laurel limestone, two miles east of Westport Indiana. This specimen is one of several from a single layer in the Laurel limestone which, at this locality, has yielded an abundance of cephalopods including a number of new species, It is associated with Leurocycloceras bucheri Flower, Virgoceras cancellatum Flower, Dawsonoceras, n. sp. Protokionoceras, n. sp. Elrodoceras indianense (Miller), Elrodoceras, n. sp., Harrisoce- ras reevesi Flower and Ormoceras, n. sp. which occur there in profusion. The only associated fossils are trilobites, Dalmanites and Bumastus, two brachiopods, Atrypa reticularis and a Cyrtina, and fragments of cystoids. Gastropods occur but are too poorly preserved for identification. The parallel arrangement of many of the cephalopod shells suggests a thanatocoenose, which, how- ever, is opposed by the occurrence here together of abundant cephalopods, trilobites and gastropods, three groups which com monly occur together in massive limestones and which, by the accumulated evidence of many such occurrences, are regarded as indicative of a natural ecological association which will be dis- cussed elsewhere as the cephalopod facies.
REFERENCES
Barrande, J. 1865-1870. Systéme Silurien du centre de la Bohéme, Pt. 1, vol. 2, Cépha- lopodes. Prague. Flower, R. H. 1939. Harrisoceras, a new structural type of orthochoanitic nautiloid. Jour. Paleont., vol. 13, pp. 473-480, pl. 49. 1941. Revision and internal structure of Leurocycloceras. Amer. Jour. Sei., vol. 239, pp. 469-488, pls. 1-8. Foerste, A. F. 1925, Notes on cephalopod genera; chiefly coiled Silurian forms. Denison Univ. Bull., Sci. Lab., Jour,, vol. 21, pp. 1-70, pls. 1-24.
a.
a ae o. &
101 INDIANA CyRTOCONIC CEFHALOPODS: I"LOWER 101
1926. Actinosiphonate, trochoceroid and other cephalopods. Denison Univ. Bull., Sci. Lab., Jour., vol. 21, pp. 285-384, pls. 32-53.
1928. A restudy of American orthoconic Silurian cephalopods. Denison Univ. Bull., Sci. Lab., Jour., vol. 23, pp. 236-320, pls. 48-75.
1928. A restudy of some of the Ordovician and Silurian cephalopods de- scribed by Hall, Denison Univ. Bull., Sei. Lab., Jour., vol. 23, pp. 173-230, pls. 40-47.
1928. American arctic and related cephalopods. Denison Uniy. Bull., Sci. Lab., Jour., vol. 23, pp. 1-11, pls. 1-29.
Miller, S. A.
1891. Paleontology. Indiana Dep. Geol. Nat. Res., Ann. Rep. 17, pp. 611- 705, pl. 1-20.
1894. Paleontology. Indiana Dep. Geol. Nat. Res., Ann. Rep. 18, pp, 257- 357, pls. 1-12.
Hyatt, A. 1884. Genera of fossil cephalopods. Boston Soe. Nat. Hist., Proe., vol. 22, p. 203-338. 1900. Cephalopoda, in Zittel-Eastmann Textbook of Paleontology, vol, 1, Ist ed., p. 502-592. Swartz, C. K. (Chairman Committee of Stratigraphy, Nat. Res. Council, Sub. committee on the Silurian system) 1942. Correlation of the Silurian formations of North America. Geol. Soe. Amer., Bull., vol. 53, pp. 533-538, 1 pl.
102 BuLuetin 109 102
VII. ANNULATED ORTHOCERACONIC GENERA OF PALEOZOIC NAUTILOIDS
ABSTRACT
A survey of Paleozoic annulated orthoceracones reveals that they are a homeomorphic and not a genetic group. The generic names which have thus far been proposed for such shells are reviewed. Some genera are so little known that they are practically useless until the types can pemre- studied. Nomenclature has been complicated by the proposal of generic names based upon superficial features of no genetic value. Restudy of genotypes makes some of these genera available.
INTRODUCTION
Annulated orthoceracones are numerous in the Paleozoic, and those of North America alone comprise over a hundred described species. Such shells first appear in the Cambro-Ordovician beds, approximately of Gasconade age, and representatives of the form- group continue upward as far as the Pennsylvanian, Sixty years ago all such species were placed in the too-inclusive genus Orthoceras along with all other straight cephalopods. Subsequent study has not only made it necessary to distinguish generically between annulated and nonannulated cephalopods, but has shown that the annulated cephalopods are in themselves polyphyletic, for annuli have clearly developed many times independently in straight cephalopods.
At the present time thirty-two generic names have been pro- posed for annulated orthoceracones. Some were proposed long ago before the structural features of cephalopods were well under- stood. Some of these are useless, while others are not only valid but useful genera. Others have been proposed as morphological investigations showed the need for new names, and a third group, based upon superficial features of the shell surface, are of value only because the types have been restudied and are found to fall into natural groups to which no earlier name could be properly applied.
103 ANNULATED ORTHOCERACONIG NAUTILOIDS: FLOWER 103
PROPOSED GENERIC NAMES
Cycloceras McCoy was the first generic name to be proposed for annulated straight cephalopods. Unfortunately the genotype, by subsequent designation (Bassler, 1915), is a species which is little known. It is not even certain whether the genus should be used for orthochoanitic or cyrtochoanitic cephalopods. Miller, Dunbar and Condra (1933, p. 45) have shown that the genotype from the Mississippian of Europe is so little known that until it is restudied, no additional species can be placed in the genus with certainty. Previously Foerste (1924, p. 224) proposed the genus Perigrammoceras, based upon Orthoceras rugosum Fleming, for species of quite similar external aspect, but Foerste (1932, p. 83) recognized that this genus could not be distinguished from Cycloceras and regarded it as a synonym. The same conclusion was reached by Miller, Dunbar and Condra (1933, p. 45). The siphuncle of the genotype of this genus is likewise unknown, and it is uncertain whether it is orthochoanitic or cyrtochoanitic. Subsequently Miller and Furnish (1938, p. 50) have used Pert- grammoceras for a species from the Mississippian of America, and Miller and Furnish (1940) have subsequently described American Mississippian annulated shells in terms of the genus Cycloceras. The reasons for these changes of view have not been stated.
Hyatt (1884, 1900) recognized several genera of annulated cephalopods and placed them in two families. Protocycloceras Hyatt, Cycloceras McCoy and Dawsonoceras Hyatt made up, with the little known Ctenoceras, the family Cycloceratide of Hyatt, while Spyroceras was placed in the family Kionoceratide, Both families were placed in the Orthochoanites, and indeed, it was not recognized at that time that there were any cyrtochoanitic annulated cephalopeds.
At the present time these genera are very differently treated. Protocycloceras Hyatt, based upon the Canadian species P. lamar-
104 BuLuetTIN 109 104
cki (Billings), was regarded as holochoanitic by Ruedemann (1906) a view of which is certainly supported by the aspect of the siphuncle wall as seen in opaque section. Thin sections, however, show that the septal necks are very short and that the wall of the siphuncle is made up of very thick connecting rings (Flower, 1941).
Dawsonoceras Hyatt based on Orthoceras annulatum Sow- by, is a valid genus characteristic of the Silurian of America and Europe in which the shell is annulated and its surface marked by transverse ridges which are festooned. The siphuncle is sub- orthochoanitic and the camere contain mural deposits, while small annuli develop in the siphuncle.
Spyroceras Hyatt, based upon Orthoceras crotalum Hall, long used for all annulated orthochoanitic orthoceracones with long- itudinal markings, has been shown to have the internal structure of a Dolorthoceras (Flower, 1939) and as such is greatly restrict- ed in scope. No species older than the Middle Devonian has been demonstrated to have this structure. The genus is at pres- ent restricted to Middle and Upper Devonian species of America and Europe. Other generic names must be employed for orth- ochoanitic shells which resemble Spyroceras externally and also for cyrtochoanitic Ordovician species of this same general aspect which are of uncertain relationship but are clearly not Pseudor- thoceratide.
Grabau and Shimer (1910) proposed Cyclendoceras based up- on Endoceras annulatum Hall of the Trenton limestone of New York for species which have the essential structure of an Endo- ceras but which have annulated shells.
Foerste and others have used Spyroceras and Cycloceras of Ordovician and Silurian species with the surface patterns regard- ed formerly as diagnostic of those genera, including within them species which were orthochoanitic, cyrtochoanitic, and sometimes intermediate between the two in the form of the segments of the siphuncle. He proposed Leurocycloceras for conchs with annuli but without longitudinal or transverse markings. That genus, based upon L. raymondi Foerste (1928, p. 272), was revised by
105 ANNULATED ORTHOCERACONIC NAUTILOIDS: FLOWER 105
the writer (Flower, 1941A) and found to contain all Silurian species of America formerly placed in Cycloceras. In the genus connecting rings are absent, and cameral deposits, episeptal and hyposeptal, may fuse within the septal foramina in advanced stag- es of growth. In the Silurian of Bohemia, however, there are shells of the aspect of Cycloceras with simple tubular siphuncles and no known deposits of the phragmocone, typified by Ortho- ceras bohemicum Barrande. No generic name is available for such species.
Metaspyroceras Foerste (1932), based upon Spyroceras rue- demanni Foerste (1921) of the Cedarville dolomite, Middle Sil- urian, was proposed for shells similar in aspect to Spyroceras but with annuli sloping orad on one side of the shell and the sutures sloping orad on the opposite side. Happily the siphuncle of the genotype is known to be orthochoanitic (Foerste, 1928, pl. 61, fig. 3A-G). This is the first genus proposed for shells similar ex- ternally to Spyroceras but with an orthochoanitic siphuncle. Sim- ilar orthochoanitic species but with transverse sutures and septa are placed in another genus, Anaspyroceras, as noted below, but the two may be very closely related.
Troedsson (1926) was the first to deliberately propose a name for cyrtochoanitic annulated orthoceracones. This is Eskimo- ceras, based upon F. boreale Troedsson of the Cape Calhoun series of the Ordovician of Greenland. The segments of the siphancle are nummuloidal and no deposits are known within the camere or siphuncle. Similar siphuncles are known in Ordovi- cian cephalopods with the exterior pattern of both Cycloceras and Spyroceras, as formerly used in the broad sense, and as the sur- face of the genotype is not known, it is uncertain to which of these groups, if either, Eskimoceras can be applied. No species other than the genotype have yet been placed in the genus.
Kobayashi (1927) described Tofangoceras for Ordovician annulated cephalopods with relatively narrow but crytochoanitic siphuncles. The genus was subsequently divided by its author (1936) so that Tofangoceras included only those species that lacked deposits in the siphuncle thcuvh having cameral deposits,
106 BULLETIN 109 106
while Tofangocerina contained all species which showed a con- tinuous lining within the siphuncle. A similar division was made at the same time between the smooth-shelled Stereo plasmoceras and Stereoplasmocerina. Unfortunately the Manchurian species which supply the basis of this work are largely fragmentary and none embrace any appreciable portion of the conch. Such differ- ences might appear in different parts of the shell of a single speci- men. They may also result from the examination of commensurate parts of the shell of individuals within a species representing various growth stages. Adoral parts of the conch of any cephal- opod bearing organic deposits may be expected to lack such struc- tures. Portions farther apicad in the Stereoplasmoceratide and Pseudorthoceratide may show cameral but no siphonal deposits. This is because these deposits show a constant and specific re- lationship to the growth of the shell in their appearance. In many cephalopods cameral deposits may appear over a very considerable interval of the phragmocone without any trace of siphonal deposits, which are frequently much more delayed in their appearance. These cameral deposits in a species may appear first in the tenth camera from the living chamber, while siphonal deposits may be delayed until the eighteenth or even later. Thus adoral and adapical parts of the same species may show the features characteristic of Tofangoceras and Tofangocerina. This is in itself no criticism of the genera, as shown by the relationship of growth stages to the biogenetic law in the Pseudorthoceratide, but where, as in the case of Tofangoceras, all known specimens are fragmentary, it presents an objection and a possible alternate explanation of the known phenomena. Until the matter can be investigated further, it seems unwise to regard Tofangoceras and Tofangocerina as distinct genera. The surface features are not well known in Tofangoceras but such markings as have been observed are fine transverse lines as in Cycloceras. Sections of some Black River species from Watertown, N. Y., closely allied to species which Foerste placed in Cycloceras show siphuncles and cameral deposits similar to the Manchurian species of Tofan- . goceras, and are properly placed in that genus,
107 ANNULATED ORTHOCERACONIC NAUTILOIDS: FLOWER 107
Miller, Dunbar and Condra (1933) erected the genus Brachycycloceras, based upon Brachycycloceras normale Miller, Dunbar and Condra of the Pennsylvanian of central North Amer- ica, for orthochoanitic conchs of cycloceroid aspect in which the sutures slope orad on one side of the shell and the annuli forward on the opposite side. Flower and Caster (1935) erected Neocy- cloceras, based upon Neocycloceras obliquum Flower and Caster, for Upper Devonian annulated orthoceracones with fine trans- verse markings, usually more or less oblique, slightly oblique sutures, and a subcentral nummuloidal siphuncle.. The internal structure is not adequately known, as no specimens have been found showing the structure of any deposits in the siphuncle. The only cyrtochoanitic cephalopods in that part of the column are the actinoceroids, which have considerably larger siphuncles, and the Pseudorthoceratide. Therefore Neocycloceras is believed to belong to the Pseudorthoceratide (Flower, 1939, p. 180) though the problem still requires investigation on the basis of better pre- served material than has yet been found.
Also worthy of mention is Cyrtospyroceras Flower (1938), based upon C. reimanni Flower of the Hamilton, a cyrtoconic shell with a marginal siphuncle similar to that of Dolorthoceras in outline. No deposits have been observed within the phrag- mocone. The genus may be a curved development from Spyro- ceras or may be only homeomorphic with it. No other possible origin of the genus has, however, been suggested.
Geisonoceroides Flower (1939) is a Middle Devonian devel- opment of the Pseudorthoceratidz in which the very slender shell bears low, rounded annuli and fine transverse markings.
Two annulated genera have been proposed among those of the Ozarkian and Canadian by Ulrich and Foerste (1935, pp. 266, 289). Catoraphiceras, based upon C. lobatum Ulrich and Foerste of the Canadian of Tennessee and described as holochoanitic, is a slightly depressed annulated shell characterized by sutures which form a narrow conspicuous lobe on the ventral (siphonal) side of the shell.
108 BULLETIN 109 108
Walcottoceras based upon Endoceras? monsensis Walcott, is a compressed annulated shell with a large marginal siphuncle re- garded as holochoanitic. In view of the ellipochoanitic or rather aneuchoanitic nature of many such siphuncles in the early Paleozoic (Flower, 1942) the holochoanitic nature of both of these genera is regarded with doubt. Catoraphiceras is Canad- ian. JValcottoceras is listed as Ozarkian. The writer has found typical representatives of that genus, however, in association with Lecanospira, Bassleroceras, Clitendoceras, Hystricurus and shells probably best placed in Pachendoceras, ina faunule which is largely a typical Canadian assemblage in the Ft. Ann quadrangle of eastern New York.
GENERA PROPOSED BY SHIMIZU AND OBATA
The above genera are those proposed up to the present with the exception of those proposed by Shimizu and Obata. Their work is best treated separately because of the special problems involved. Thus far all except a very few of the genera have been based upon species which were well enough known so that they could be easily recognized. Indeed, the only exceptions to this at the present time are the Mississippian genotypes of Cyclo- ceras and Perigrammoceras. Foerste, and most other authors, had applied Spyroceras and Cycloceras, broadly to include species which together ranged fairly well through the lower part of the Paleozoic, though conscious of their error in doing so. This procedure was apparently adopted because it was felt that the al- ternate step, the proposal of new generic names, should await a more thorough study of the species involved, and in particular, the use of adequately known genotypes. Shimizu and Obata (1935, 1936) displayed none of these inhibitions, observations almost completely upon the publishe Foerste, Kobayashi and Endo, they have proposed ber of generic names, and quite a few famil upon minor differences in the surface fe conjunction with fine distinctions between uncular segments. misle
Basing their d works of a large num- y names, based largely atures of the shell, in various types of siph-
In both respects their statements are often
ading and sometimes deliberately false. The generic names
109 ANNULATED ORTHOCERACONIC NAUTILOIDS: FLOWER 109
which they have proposed have thus far not been employed to any considerable extent by other authors. Were the differences, which they mention the criteria for the recognition of their genera, their work might well be consigned to the oblivion which it so richly deserves. However, a generic name, if proposed under certain conditions, chief among which is the use of a genotype, is valid from a nomenclatorial point of view however absurd its description may be. When such names are proposed for a group of organisms in which new generic divisions are needed, they must be considered, for subsequently described genera run the danger of being reduced to synonymy. It should be noted that there are no generic names among those so far considered for the follow- ing types of annulated cephalopods:
t. Annulated species with longitudinal markings and an orth- ochoanitic siphuncle, and simple transverse sutures.
2. Annulated cephalopods with longitudinal markings and a cyrtochoanitic siphuncle, lacking deposits of the Pseudortho- ceratide, and either empty or with annular deposits.
3. Orthochoanitic shells with the aspect of Cycloceras.
4. Cyrtochoanitic shells with the aspect of Cycloceras but with simple sutures.
Such species are abundant in the Ordovician and Silurian, and generic names are needed for them. It is necessary to determine first whether any of the generic names already proposed can be used for such species.
In the following pages the genera proposed by Shimizu and Obata are analysed in as far as the resources available to the writer permit. Some genera are based upon species which are so inadequately known that no other species can be assigned to the genus with certainty.* In other cases the genotypes have yielded adequate structural information.
Before proceeding to a detailed analysis of the genera, a brief survey of the results of this investigation is presented.
* In some instances the genotypes are known only from single speci-
mens. The rarity of the species and the poor preservation of internal structure characteristic of the beds in which they occur (as in parts of the Trenton of New York) makes it improbable that they will ever be well enough known to serve as useful genotypes.
110 BuLuetTiIn 109 110
Family SPYROCERATIDZE Shimizu and Obata
This name is abandoned. It was proposed for orthochoanitic genera of the external aspect of Spyroceras, ignoring completely that the genotype of Spyroceras, S. crotalum (Hall 1876) has a cyrtochoanitic siphuncle. Subsequently the writer (1939) has demonstrated that Spyroceras is properly placed in the Pseudor- thoceratide. The genera which Shimizu and Obata placed in the Spyroceratide are as follows:
Eospyroceras.—A subjective synonym of Metaspyroceras Foerste.
Hypospyroceras.—Inadequately known. The genotype is ap- parently known only from the type, which does not show the nec- essary internal structure.
Subs pyroceras.—Until the siphuncle of the genotype is made known, no other species can be placed in this genus.
Anaspyroceras.—The genotype is_ orthochoanitic. The genus must be used for orthochoanitic shells of the external aspect of Spyroceras, with transvers annuli and sutures. It may, however, grade into Metaspyroceras.
Gorbyoceras.—Sections of the genotype yielded a cyrtochoanitic siphuncle, contrary to the exception of Shimizu and Obata who placed it in the orthochoanitic Spyroceratide by faith alone. The segments of the siphuncle are similar in form to those of relative- ly early stages of Treptoceras. It is uncertain whether this genus, like Treptoceras, is an actinoceroid, or whether it belongs to some other group.
Family HAMMELLOCERATIDZ
This name is dropped because the type genus is not recognized. It was proposed for cyrtochoanitic shells externally like Spyro- ceras.
Hammelloceras.
A subjective synonym of Gorbyoceras. Cedarvilloceras——A_ subjective synonym of Dawsonoceras Hyatt. The siphuncle is not properly cyrtochoanitic,
ililal ANNULATED ORTHOGERACONIG NAUTILOIDS: FLOWER 111
Family CYCLOCERATIDE Hyatt
As emended by Shimizu and Obata, this family is confined to orthochoanitic annulated shells with transverse markings. That the siphuncle of Cycloceras itself is unknown is a fact which they treat with an indifference amounting to apathy. Besides Cyclo- ceras they place in it:
Paleocycloceras.—A subjective synonym of Protocycloceras.
Foersteoceras—A homonym of Foersteoceras Ruedemann. Properly, the family Cycloceratidze can contain only the type genus until Cycloceras itself is more adequately known.
Family ESKIMOCERATID Shimizu and Obata
As the genotype is not known to have transverse markings, the family cannot be used for such shells. Two new genera are placed here with Eskimoceras.
Pseudeskimoceras.—A subjective synonym of Tofangoceras.
Kogenoceras.—A subjective synonym of Tofangoceras.
GENERA PROPOSED BY SHIMIZU. AND OBATA FOR SHELLS OF MEE EXChERNAL ASPECT OF SPYRO- CERAS (SPYROCERATIDA: AND HAMMELL- OCERATIDA OF SHIMIZU AND OBATA)
Genus EOSPYROCERAS Shimizu and Obata Genotype —Orthoceras arcuoliratum Hall (1847, p. 198, pl. 42, fig. 7). Original description ‘Genotype Orthoceras arcuoliratum Hall from the Middle Ordovician of North America. The ex-
tremely arching or undulating annulations and fine longitudinal striae of this genus serve to distinguish it from the other known
ni? BULLETIN 109 112
representatives of Spyroceratide. Although the siphuncular structure of the genotype is unknown, it is provisionally included in Spyroceratide.”
It is obviously impossible to use this generic name until the condition of the siphuncle is known for the genotype. Happily, a hypotype in the collection of the University of Cincinnati Mu- seum, No. 10452, from the Trenton limestone near Theresa, New York, has revealed a portion of the siphuncle, sufficient to show that it was orthochoanitic and perfectly tubular. This generic name can therefore be used for orthochoanitic annulated cephal- opods with longitudinal markings. Unfortunately, however, the slope of the annuli in the genotype is very close to that of Metas- pyroceras Foerste (1932). No specimens of the genotype are known which preserve the sutures clearly enough to show wheth- er they slope in a direction opposite to that of the oblique annul or not. Even if the sutures are straight and transverse, there is no clear dividing line between such species and those in which the sutures as well as the annuli are oblique. Therefore, I tenta- tively regard Eospyroceras as a subjective synonym of Metaspy- roceras Foerste. Foerste (1928, 1932) placed Orthoceras arcuo- hiratum Hall in Spyroceras while in the same work he placed some other species in Metaspyroceras. The distinction applied by Foerste is not altogether clear. Apparently only those species with markedly oblique sutures and annuli were placed in Met- aspyroceras, while those with oblique as well as transvers annuli but with sutures which were either relatively straight and trans- verse, or poorly shown, were placed in Spyroceras, sensu lato. The problem of the generic distinction in such species is one to which there seems to be more than one possible nomenclatorial solution. However, in view of the present restriction of Spyro- ceras to members of the Pseudorthoceratidz, the question is no longer what species may be placed in Spyroceras, but what ones can properly be included in Metaspyroceras. Spyroceras cannct properly be applied to any known pre-Devonian cephalopod. Met- aspyroceras is the first genus proposed for orthochoanitic shells
113 ANNULATED ORTHOCERACONIG NaAUuTILOIDS: FLOWER 113
of the external aspect of Spyroceras, and as such might possibly be extended to include all such shells which range from Ordovic- ian though the Silurian and possibly even higher. In the present work, however, Metaspyroceras is confined to shells in which the annuli are oblique, though more latitude is allowed the condi- tion of the sutures than was done by Foerste, largely because it is believed that no natural distinction can be made on this basis.
Genus HYPOSPYROCERAS Shimizu and Obata Genotype.—Orthoceras teretiforme Hall
Original description.—“H ypospyroceras, gen. nov. Genotype; Orthoceras tretiforme Hall... . from the Ordovician of North America. This genus is characterized by its slightly undulating broad annulations marked with coarse longitudinal striae.”
Orthoceras teretiforme Hall (1847, p. 198, pl. 42, fig. 8) (see also Foerste, 1932, p. 98-100, pl. 11, fig. 5A-B) is the genotype. There is no such described species as Orthoceras tretiforme Hall which is obviously a misprint. The nature of the siphuncle is unknown in this species. Consequently until it is known, the generic name cannot be applied to either orthochoanitic or cyrto- choanitic annulated shells. Foerste (1932) figures only a part of the original type specimen. The remainder is apparently lost. Insofar as the writer has been able to determine, this species seems to be known only from this small specimen. It is inadequate as the basis of a genus, which in the last analysis, it is. The annuli are slightly oblique as in Metaspyroceras Foerste and its synonym Eospyroceras Shimizu and Obata. The annulations are not so broad as indicated in Hall’s original drawing, and the surface features noted by Shimizu and Obata are not adequate for the rec- ognition of the genus which is not only unrecognizable in its pres- ent state but is regarded tentatively as a subjective synonym of Metaspyroceras Foerste.
Genus SUBSPYROCERAS Shimizu and Obata (1935, p. 4)
Genotype.—Spyroceras middlevillense Foerste (1928, Denison Univ. Bull., Sei. Lab., Jour., vol. 23, p. 178, pl. 40, fig. 3A-B).
Original description —‘‘This genus is similar to typical Spyro-
114 BULLETIN 1°03 114
ceras but with more prominent annulations and coarser, stronger, longitudinal striae. Orthoceras olorus Hall [1847, p. 201, pl. 43, fig. 5] and O. clathratum Hall [J/bid.] from the middle Or- dovician of North America, assigned by Foerste to Spyroceras, may belong to Subspyroceras. Beside it Spyroceras orientale Kobayashi [1934, p. 425, pl. 21, fig. 8-11] from the Middle Ord- ovician of Korea and Spyroceras, sp. indet. [in Endo, 1932, p. 73, pl. 38, fiz. 5] from the Ordovician of Shensi, China are referred to Subspyroceras.”
In the above only the method of citation of the species men- tioned has been changed to make it intelligible without the bib- liography of Shimizu and Obata.
The siphuncle is unknown, Until it has been studied in the genotype, it cannot be said for certain whether the genus is orthochoanitic or cyrtochoanitic. Similar species, with prominent transverse annuli and coarse surface markings, in the Chazyan, Black River and Cincinnatian, which have been studied by the writer, are both orthochoanitic, having perfectly tubular siph- uncles, and cyrtochoanitic, having considerably expanded siph- uncles. Obviously two genera are involved, but in the present state of ignorance of Subspyroceras, that name which should never have been proposed upon such meagre data, cannot be applied to either group of species.
Genus ANASPYROCERAS Shimizu and Obata (1985, p. 4)
Genotype.—Orthoceras anellum (Conrad, 1843, (see also Foerste, 1928, p. 177, pl. 40, fig. 4). Beloit member, Black River formation, Mineral Point, Wisconsin.
Original description.—-‘This genus is readily distinguished from Spyroceras by its more crowded, stronger annulations, Dawson- oceras ? aequilonare Troedsson [1926, p. 79, pl. 9, fig. 2-4, in- correctly included by Foerste (13, p. 162) in Spyroceras] from the Ordovician of Greenland, and Spyroceras fritzi Foerste (13, p. 163, pl. 37, fig. 2) from the middle Ordovician of North Amer-
ica probably belong to Anaspyroceras.”
115 ANNULATED ORTHOCERACONIC NAUTILOIDS: FLOWER 115
The criteria upon which this genus was based by Shimizu and Obata seem even more absurd when it is remembered that such species as Spyroceras lima and S. thestor, typical members of the genus from the Hamilton of New York might be included here as easily. As usual, Shimizu and Obata have selected as a genotype of a new genus in their presumably orthochoanitic Spyroceratide a species for which the form of the siphuncle is unknown. Study of a specimen in the collections of the University of Cincinnati Mu- seum revealed the presence of straight septal necks in the species, but failed to show connecting rings. The genus can, then, be used for orthochoanitic conchs of the aspect of Spyroceras. Its use seems a necessary step. Unfortunately there is no certainty that future study may not show that it is not distinct from the inadequately known genus Subspyroceras which precedes it in the descriptions of Shimizu and Obata. Should this occur, that genus would have to be considered as having page priority.
Genus CEDARVILLOCERAS Shimizu and Obata
Genotype.—Dawsonoceras nodocostatum (McChesney) Foerste (1928, p. 276, pl. 58, fig. 3, pl. 59, fig. 1) Silurian of North America.
Original description—This genus differs from the typical Dawsonoceras chiefly in having narrow but distinct equidistant longitudinal ridges crossing the annulations. We believe it to be a derivative of the Ordovician anaspyroceratid stock, which has much finer longitudinal ridges. The specimen figured by Patte as Orthoceras pseudocalamiteum (not Barrande) from the Gotland- ian of Yunnan, China, has not the same form as the species of Barrande. It appears to be referable to Cedarvilloceras.”
Study of American species of Dawsonoceras shows, however, that D. nodocostatum represents one of two extremes in the mod- ification of the ornament. Internally it is typical of Dawsonocer- as, and grades into it through such allied forms as D. hyatti Foerste and D. bridgeportense Foerste. As I am unable to find any good point of division between this and typical Dawsonoceras, this new generic name is one for which it does not seem possible to find any good use, Therefore Cedarvilloceras is regarded as a
116 BULLETIN 109 116
subjective synonym of Dawsonoceras. The genus is common in the Silurian of America, and it is represented by a considerable number of species which are very closely related. (Flower, 1942, p. 12-17.) It is also well developed in the European Silurian.
Genus GORBYOCERAS Shimizu and Obata
Genotype.—Orthoceras gorbyi Miller, 1894. (See also Foerste, 1928, p. 283, pl. 41, fig. 4a-c.) Richmond. Upper Ordovician, Ohio and Indiana.
Original description —‘This genus is characterized by possess- ing peculiar annulations and distinct longitudinal striae; the an- nulations sloping downward and weakening toward the venter.”
Although this genus is placed among the Spyroceratide by Shimizu and Obata and is therefore presumably regarded as orthochoanitic by them, no description had up to that time in- cluded any mention of the structure of the siphuncle of the gen- otype. That species has been restudied on the basis of a good suite of specimens from the collections of the University of Cincinnati and of Dr. W. H. Shideler of Miami University. The siphuncle is found to be cyrtochoanitic, made up of broadly oval segments with strongly recurved short septal necks, and is indistinguish- able in outline from the siphuncle of early ephebic Treptoceras Flower. Further, the earliest part of the shell sectioned shows small annulosiphonate deposits. These facts suggest strongly that Gorbyoceras may be a member of the Sactoceratide of the Actinoceroidea. The cyrtochoanitic nature of the siphuncle is all that preserves the name of Gorbyoceras, for it happens to be the first generic name proposed in connection with a cyrtochoanitic shell of the aspect of Spyroceras with broadly rounded siphuncular segments and small annulosiphonate deposits. Such species are widespread in the Ordovician, ranging from the Chazyan Spy- roceras clintoni (Miller) (see Ruedemann, 1906) to the genotype and allied species of Richmond age. It has page priority over Hammelloceras Shimizu and Obata, discussed below and Port- eroceras Shimizu and Obata. These generic names are proposed for cyrtochoanitic conchs of very similar aspect, but distinguished, as noted below, upon the basis of details of the surface sculpture. The perpetuation of Gorbyoceras rests upon the rules of zoological nomenclature and upon page priority and not upon a single one of
Ly ANNULATED ORTHOCERACONIC NAUTILOIDS: FLOWER Maly
the features mentioned in the above quoted description of Shimizu and Obata. Oblique annuli are found in other conchs of spyrocer- oid aspect, even in Spyroceras, sensu stricto in the Devonian. S'py- roceras oppletum Flower (1939) of the Tully limestone, a typical Spyroceras internally, has low annuli which may fade out on one side of the shell. Equally oblique annuli are to be found in both orthochoanitic and cyrtochoanitic shells with the ornament of Spyroceras. Indeed, externally, the oblique annuli and sutures makes Gorbyoceras an almost perfect homemorph for Metaspy- roceras Foerste, the only difference shown on the exterior of typical specimens being the tendency for the annuli to weaken and disappear on the ventral side of Gorbyoceras. This is a feature not constant even in the genotype, as shown by the study of a considerable series of specimens.
Revised description—Conch orthoceraconic, rarely slightly curved, with annuli and longitudinal markings. In the genotype the siphuncle is broadly cyrtochoanitic, with very short septal necks and segments of rounded outline, similar to those of early ephebic Treptoceras. The obliquity of the annuli and sutures is not a constant feature, nor is the low rounded condition of the annuli. Such general and obvious differences in the shells have failed to show any stratigraphic or paleogeographical uniformity and I can discover no good reason for subdividing the genera as at present established on the basis of such features. The scg- ments of the siphuncle are broader than in Spyroceras and siphonal deposits do not line the siphuncle as in the Pseudortho- ceratide.
Genus HAMMELLOCERAS Shimizu and Obata
Genotype—Dawsonoceras hammelli Foerste. (1910, p. 74, pl. 1, fig. 4). Richmond, Ohio and Indiana.
Original description ‘Externally this genus is somewhat sim- ilar externally to Kionoceras except that is has prominent an- nulations and an ormoceratoid siphuncle.”’
Shimizu and Obata are correct in attributing to the genotype of this genus a cyrtochoanitic siphuncle. However, such a siphuncle is also to be found in Gorbyoceras, a fact of which they were ignorant when placing that genus in the supposedly or-
118 BULLETIN 109 118
thochoanitic Spyroceratide. Dawsonoceras hammelli is very closely related to Orthoceras gorbyi with which it is associated in the upper Richmond of Indiana and Ohio, In the same as- sociation are found other species which are intermediate be- tween these two in the features of the annuli, surface markings, and sutures. Further, the early stages of gorbyi and hammelli are so similar that I am not certain that they can always be distinguished. With such close relationship between the geno- types, two generic names in such a group of closely allied species are things for which I can discover no good use. Therefore Hammelloceras Shimizu and Obata is suppressed as a synonym of Gorbyoceras Shimizu and Obata.*
Genus PORTEROCERAS Shimizu and Obata
Genotype.—Spyroceras porteri Schuchert. (See Foerste, 1928, p: 37, ple 7, fig. 2A-B; pl. 23, fig. 4.) Trenton or Upper Ordovician, Baffin Land.
Original description—‘Genotype: Spyroceras portert (Schu- chert) Foerste from the Upper Ordovician? of Canada. This genus although related to Hammelloceras differs from it in pos- sessing more prominent ornamentation and sactoceroid siphuncle. Orthoceras bilineatum Hall 13, p: 200, pl. 43, fig. 3 = O. annal- lum Hall 6, pl. 43, fig. 6d-f only, incorrectly assigned by Foerste [7, (1928) p. 180, pl. 40, fig. 5A-B] to Spyroceras, and Spyrocer- as bilineatum var. alpha (Hall) Foerste [7 (1928) p. 180, pl. 40, fig. 7] from the Middle Ordovician of North America, probably belongs to Porteroceras although the structure of the siphuncle is unknown.”
The “more prominent ornament” by which this genus is set apart from that based upon Orthoceras hammelli is a difference
* Tn the revision of the Cincinnatian nautiloids of the Cincinnati re-
gion, a work which is now more than half completed, G. gorbyi, G. ham- melli and associated and closely related species are deseribed and illus- trated. One undescribed form is clearly intermediate between G. gorbyi and G. hammelli so that the recognition of two genera based upon these species is not only manifestly absurd, but impossible.
119 ANNULATED ORTHOCERACONIC NAUTILOIDS: FLOWER 119
not well supported by Foerste’s photographs of the type, and one which disappears when more and better preserved material of O. hammelli is studied. The sactoceroid rather than ormocera- toid siphuncle, a distinction of which Shimizu and Obata appear to be fond, is of very dubious merit and validity. The relatively narrow siphuncle which they consider “‘sactoceratoid” rather than “ormoceratoid’” may so easily be due to a section which does not quite attain the center of the siphuncle, that its use as a generic feature seems unwise. Further, the difference between the form of the segments of the siphuncle as shown by the two genotypes is not, in the opinion of the writer, great enough to serve as a basis of generic separation. Therefore Porteroceras is here regarded as a synonym of Gorbyoceras of which Ham- melloceras 1s also a synonym.
CENERA OF ANNULATEDS=CEPHALORODS WILLE TRANSVERSE, MARKINGS, PROPOSED BY SHIMIZU AND OBATA
Family CYCLOCERATID: Hyatt
Shimizu and Obata (1936, p. 19) emend this family to “or- thochoanitic annulated orthoceracone and cyrtoceracone with transverse striae and without longitudinal ridges or striae.” In- asmuch as Cycloceras is so little known that only the genotype can be placed in it, the family Cycloceratide can not contain any other genus than the inadequately known Cycloceras, and is at the present time of no real value in the scheme of cephalopod classification. Shimizu and Obata place two new genera in this family which have been previously commented upon by the writer (Flower, 1941, p. 475-477). Paleocycloceras Shimizu and Obata was erected on the basis of a supposition and was believed to be ellipochoanitic, whereby it is distinguished according to Shimizu and Obata, from Protocycloceras. However, thin sectiors of the siphuncle of the genotype of Protocycloceras show that it is ellipochoanitic and eurysiphonate in the complex thick con- necting ring (Flower, 1941A). Therefore, if Shimizu and Obata
120 BULLETIN 109 120
are correct in their supposition, there is still no good difference between Protocycloceras and Paleocycloceras. In any case, the new name should not have been proposed on the basis of a sup- position.
Foersteoceras Shimizu and Obata, as pointed out independent- ly by Teichert (1941) and Flower (1941), is a homonym of Foersteoceras Ruedemann (1926). Further, both authors agree that until more is known about orthochoanitic Ordovician conchs of the general aspect of Cycloceras, there 1s no virtue in proposing a new name for this group of species.
Family ESKIMOCERATIDZ Shimizu and Obata
The family Eskimoceratidz was erected by Shimizu and Obata (1936, p. 22) for “Cyrtochoanitic annulated orthoceracone and cyrtoceracone without longitudinal ridges or striae.’ In it were placed besides Eskimoceras Troedsson (1926) two new genera. Little is known of the surface of Eskimoceras, and there is no information as to the nature of any deposits of the interior of the phragmocone, and there is no certainty that it forms a natural family with any other annulated cephalopods. The two new gen- era are summarized below.
Genus PSEUDESKIMOCERAS Shimizu and Obata
“Genotype: Cycloceras ? manchuriense Endo (1932, p. 68, pl. 14, fig. 8, 9, 12.) Diagnosis: Annulated orthoceracone, sub-cir- cular in cross section, annulation oblique and less numerous than number of septa. Siphuncle moderate in size, subcentral and ormoceratoid.
“Remarks: This genus is close to Eskimoceras, from which it is distinguished by having oblique test annulation and by its septa outnumbering the annulation.”’
The surface of the shell of the genotype is.so poorly preserved that Endo was not certain that it fell into the broad group to which Foerste and others applied the name Cycloceras in a broad sense. Similar species from the Black River of New York and Ontario have been studied by the writer (unpublished) and are regarded as typical of Tofangoceras, which Shimizu and Obata
121 ANNULATED ORTHOCERACONIC NAUTILOIDS: FLOWER 121
incorrectly regard as orthochoanitic. Pseudeskimoceras is here regarded as a subjective synonym of Tofangoceras Kobayashi.
Genus KOGENOCERAS Shimizu and Obata
“Genotype.—T ofangoceras huroniforme Kobayashi (1934, p. 435, pl. 27, fig. 9-11, 14.)
“Diagnosis: Cyrtochoanitic annulated orthoceracone, circular in cross section, with narrow eccentric siphuncle, characterized by Huromia-like segments.
“Remarks: The genotype of this genus, which was erroneously referred by Kobayashi to Tofangoceras, differs sufficiently from the latter true Tofangoceras belonging to the orthochoanites to justify the creation of a new genus, Kogenoceras, gen. nov.
‘This genus resembles Pseudeskimoceras, but nas Huronta- like siphuncular segments instead of the sactoceratoid siphuncular segments of the latter.”
The segments of the siphuncle are not nearly so similar to those of Huronia as this description would lead one to believe. They are expanded segments in which expansion is more abrupt at the adoral end, at the septal neck, than at the adapical end. The deposits of the camere are typical of the Stereoplasmocer- atidee and of Tofangoceras . The deposits of the siphuncle are of the type for which Kobayashi has erected the genus Tofangoce- rina. As noted above, it is very possible that this genus may not be distinct from Tofangoceras but shows an apparent difference owing to examination of individuals representing different growth stages of fragmentary shells.
There is no basis for the recognition of Kogenoceras as distinct from Tofangoceras.
SUMMARY OF PALEOZOIC ANNULATED CEPHALOPOD GENERA
I. Early Paleozoic pre-Champlainian genera, Internal structure where known shows eurysiphonate connecting rings. Walcottoceras Ulrich and Foerste, 1935. Small compressed annulated shells with a marginal and reputedly holochoanitic siphuncle. Regarded by Ulrich and Foerste as Ozarkian, but
122 BULLETIN 109 122
found by the writer in the Canadian in association with Basslero- ceras, Clitendoceras, Lecanospira, Hystricurus and a cephalopod regarded as the supposedly Ozarkian genus Pachendoceras Ul- rich and Foerste in the Fort Ann quadrangle, eastern New York.
Clitendoceras Ulrich and Foerste, 1935. Circular to depressed annulated shells readily recognized by the small narrow lobe formed on the venter. Canadian.
Protocycloceras Hyatt. Circular to depressed annulated cepha- lopods with simple sutures and a large submarginal siphuncle, ap- parently holochoanitic, but made up of aneuchoanitic necks and complex thick rings. Canadian, North America.
Peleccycloceras Shimizu and Obata.—Synonym of Protocylo-
ceras. Canadian of Manchuria. II. Stenosiphonate annulated genera of the external aspect of Spyroceras.
Metaspyroceras Foerste. Ordovician and Silurian ortho- choanitic forms. Typically the sutures slope forward on one side, the annuli on the other. Such typical species grade into others in which the annuli are oblique but the sutures essentially transverse.
Eospyroceras Shimizu and Obata. Here regarded as a sub- jective synonym of Metaspyroceras Foerste.
Hypospyroceras Shimizu and Obata. Inadequately known. No species other than the genotype can be assigned to it.
Subspyroceras Shimizu and Obata. Inadequately known.
Anaspyroceras Shimizu and Obata, emend. Flower. This is the first generic name which has been proposed with a genotype known definitely to have the external aspect of a Spyroceras with simple transverse sutures and an orthochoanitic siphuncle. As such it is being employed elsewhere by the writer. It is probably related to Metaspyroceras and may, it is feared, grade into that genus.
Gorbyoceras Shimizu and Obata, emend. Flower. This genus was inadvertently applied by its authors to a cyrtochoanitic spe- cies. It is the proper receptacle for shells with the external
123 ANNULATED ORTHOCERACONIC NAUTILOIDS: FLOWER 123
aspect of Spyroceras but with nummuloidal siphuncles. Cameral deposits are developed. Small annulosiphonate deposits are known, suggesting that this genus may be an actinoceroid. The internal structure is quite similar to that of Treptoceras, but no portions of the shell are known showing the siphonal deposits in a growth stage sufficiently advanced to show whether they are actinoceroid in their structure. Ordovician, Chazyan through Richmond,
Hammelloceras Shimizu and Obata. A subjective synonym of Gorbyoceras.
Porteroceras Shimizu and Obata. A subjective synonym of Gorbyoceras.
Spyroceras Hyatt. Middle and Upper Devonian.* Annulated shells with longitudinal markings. The siphuncle is similar to that of Dolorthoceras Miller. The deposits of the siphuncle are typical of the subfamily Dolorthoceratine of the family Pseudor- thoceratide. In the broad sense Spyroceras was formerly used for nearly all annulated cephalopods with longitudinal ornament. III. Surface markings not definitely known.
Eskimoceras Troedsson, A valid genus of annulated cyrto- choanitic cephalopods. It is uncertain whether the surface is smooth, or whether originally longitudinal markings were pres- ent as in Spyroceras, sensu lato, or transverse markings such as in Cycloceras, sensu lato. Ordovician. Thus far recognized only in Greenland.
T ofangoceras Kobayashi. Annulated cephalopods with a cyrto- choanitic siphuncle, rather variable in the form of the segments, variation apparently having much to do with the growth stage examined. Cameral deposits are well developed. Species show- ing parietal deposits within the siphuncle are placed here by the writer. Ordovician.
* Possibly also Lower Devonian. Nothing, however, is known of the
internal structure of Spyroceras-like Lower Devonian shells and their gen- erie position is uncertain.
124 BULLETIN 109 124
Tofangocerina Kobayashi. Regarded here as not distinct from Tofangoceras. The genus was erected for species of Tofangoceras showing clear deposits within the siphuncle.
Kogenoceras and Pseudeskimoceras Shimizu and Obata, — Synonyms of Tofangoceras Kobayashi.
IV. Annulated orthoceracones with transverse marking.
Cyclendoceras Grabau and Shimer. Holochoanitic endoceroids with low annuli. Ordovician.
Foersteoceras Shimizu and Obata——Homonym of Foersteo- ceras Ruedemann.
Leurocycloceras Foerste—Confined to species with specialized internal structure. Annuli may be low and flat, interspaces ap- pearing as narrow grooves. Silurian, North America and Europe.
Dawsonoceras.—Silurian. Transverse markings scalloped and festooned. Secondary longitudinal markings sometimes devel- oped.
Cedarvilloceras Shimizu and Obata-—Synonym of Dawsono- ceras.
Neocycloceras Flower and Caster. Cyrtochoanitic, with ob- lique annuli and sutures. Upper Devonian and Mississippian. Internal structure poorly known, probably best placed in Pseudor- thoceratide,
Brachycycloceras Miller, Dunbar and Condra. Orthochoanitic rapidly expanding annulated shells of the aspect of Cycloceras, sensu lato, with sutures and annuli slightly inclined in opposite directions. Pennsylvanian,
Cycloceras McCoy. Annulated cephalopod. Mississippian. Gen- otype inadequately known; no other species can be placed in the genus properly.
Perigrammoceras Foerste. <A subjective synonym of Cy- cloceras. The siphuncles are not known in the types of either genera.
Geisonoceroides Flower. Slender pseudorthoceroids with low
it = s cP eee zi equent annul: and fine transverse markings. Middle and Upper Devonian of New York.
125 ANNULATED ORTHOCERACONICG NAUTILOIDS: FLOWER 125
PUVLOGENE TIC NOTES
Annulations on straight shells are clearly no good mark of relationship of genera, as shown by the exceedingly diverse in- ternal structures. In the early Paleozoic the eurysiphonate line, characterized by thick connecting rings, gave rise at least to one annulated shell, Protocycloceras, and probably to Walcottoceras and Catoraphiceras, two genera which are not well enough known structurally to permit the tracing of their precise relations. There is no reason to believe that they form a natural group among early Paleozoic cephalopods with Protocycloceras.
In the Champlainian shells of spyroceroid aspect but with cyr- tochoanitic siphuncles appear. Such forms, believed to be best placed tentatively in the Stereoplasmoceratide, form a natural group ranging from the Chazyan (G. clintont S. A. Miller) to the Richmond, and among the various generic names previously proposed, Gorbyoceras is the only one which can legally be ap- plied to them in accordance with the rules of zoological nom- enclature and the present knowledge of cephalopod genotypes.
Orthochoanitic shells of the external aspect of Spyroceras are found in association with these forms. Sometimes it is impossible to distinguish between the two groups without the aid of sections. Such species are placed in Anaspyroceras Shimizu and Obata and in Metaspyroceras Foerste.
Shells of spyroceroid aspect in the Silurian are little known. A few orthochoanitic species are found in this part of the column which are probably best placed in Anaspyroceras. The genotype of Metaspyroceras is Silurian, but more Ordovician than Silurian species are known in the genus.
In the Middle Devonian the genus Spyroceras developed within the secondary cyrtochoanitic family Pseudorthoceratide. No spe- cies are known except in the Middle and Upper Devonian which can be assigned to Spyroceras in the strict sense. Higher in the column no shells of spyroceroid aspect are known.
The Middle Ordovician of Manchuria contains annulated ceph- alopods of the Stereoplasmoceratide belonging to the genus To-
126 BULLETIN 109 126
fangoceras Kobayashi, Some Middle Ordovician species of Amer- ica, formerly placed in Cycloceras, sensu lato, show the features of this genus. The siphuncle is cyrtochoanitic, though variable in form with the growth stages, the early segments being more expanded than the later ones, which approach and may even at- tain a suborthochoanitic condition, Eskimoceras is generally considered with shells of cycloceroid aspect, although the surface is unknown. It is cyrtochoanitic, but no deposits are known and it is therefore uncertain whether it is related to Tofangoceras or whether it represents an independant development. No generic name is available for Ordovician and Silurian orthochoanitic spe- cies of the external appearance of Cycloceras. Such forms exist in the upper Ordovician of North America and in the Silurian of Europe. .
Leurocycloceras, proposed for shells presumably without transverse markings, is found to be the dominant cycloceroid genus of the American Silurian. It is orthochoanitic, and pe- culiar in the mode of growth of the deposits of the phragmocone as well as in the absence of connecting rings. (Flower, 1941A.)
The next cycloceroid conch found is Neocycloceras Flower and Caster, a cyrtochoanitic shell doubtfully assigned to the Pseudorthoceratidz, largely because no other family is known in that part of the column which develops small cyrtochoanitic siphuncles in straight cephalopods. Neocycloceras ranges from the Upper Devonian (Conewango) into the basal Mississippian.
Mississippian annulated cephalopods which have been assigned to Cycloceras and Perigrammoceras are essentially cyrtochoanitic, though no deposits have been made known in the siphuncles, and their relationship is therefore still obscure. It is not even cer- tain that deposits are naturally absent in these forms, as the American Mississippian is an unfavorable medium for preserva- tion of internal structure of cephalopods in most instances.
The next occurrence of cycloceroid conchs, and the last, is found in the orthochoanitic Brachycycloceras of the Pennsylvan- ian,
From the above summary it can be seen that annulated ceph-
127 ANNULATED ORTHOCERACONIC NAUTILOIDS: FLOWER 127
alopods have developed in many different structural groups. Some are still very inadequately known, but it is clear that such a shell form has developed several times in the pre-Champlainian eurysiphonate cephalopods, once in the true MHolochoanites which as defined by Hyatt, is a part of the Endoceroidea, and many times among the ellipochoanitic stenosiphonate forms which dominate from the Champlainian to the close of the Paleozoic. Annuli have appeared in the Pseudorthoceratide, in the Stere- oplasmoceratide, and in orthochoanitic orthoceracones. A num- ber of cyrtochoanitic genera of uncertain origin remain to be traced which are isolated either by the form of the segments of the siphuncle, deposits or absence of deposits, and stratigraphic range, all three frequently contributing.
REFERENCES
Barrande, J.
1865-1870. Systéme Silurian du centre de la Bohéme. Céphalopodes. Pt.
1, vol. 2. Prague. Endo, R.
1932. The Canadian and Ordovician formations and fossils of south Man-
churia. U. 8. Nat. Mus., Bull. 164, 152 pp., 40 pls. 1 map. Flower, R. H.
1938. Devonian brevicones of New York and adjacent areas. Paleonto- graphica Americana, vol. 2, No. 9, 84 pp., 4 pls., 10 figs.
1939. Structure of the Pseudorthoceratide. Paleontographica Americana, vol. 2, No. 10, 214 pp., 9 pls., 22 figs.
1941. Notes on structure and phylogeny of eurysiphonate cephalopods. Paleontographica Americana, vol. 3, No. 13, 56 pp., 3 pls., 3 figs.
1941A. Revision and internal structure of Leurocycloceras. Amer. Jour. Sci., vol. 239, pp. 469-488, pls. 1-3.
1942. Cephalopods from the Clinton group of New York. Bull. Amer. Paleont., vol. 27, 28 pp. 2 pls.
Flower, R. H., and Caster, K. E.
1935. The stratigraphy and paleontology of northwestern Pennsylvania. Part II: Paleontology. Sec. A: The cephalopod fauna of the Cone- wango series of the Upper Devonian in New York and Pennsylvania. Bull. Amer. Paleont., vol. 22, No. 75, 1935.
Foerste, A. F.
1928. American arctic and related cephalopods. Denison Univ. Bull., Sci. Lab., Jour., vol. 23, pp, 1-110, pls. 1-29.
1928. A restudy of some of the Ordovician and Silurian cephalopods de- scribed by Hall. Denison Univ. Bull., Sci. Lab., Jour. v,ol. 23, pp. 173, 230, pls. 40-47.
1928. A restudy of American orthoconic Silurian cephalopods. Denison Univ. Bull., Sci. Lab., Jour., vol, 23, pp. 236-320, pls. 48-75.
1932. Black River and other cephalopods from Minnesota, Wisconsin,
128 BULLETIN 109 128
Michigan and Ontario. Part I. Denison Univ. Bull., Sci. Lab., Jour., vol. 27, pp. 47-136, pls. 7-37. Kobayashi, T.
1931. Studies on the Ordovician stratigraphy and paleontology of north Korea with notes on the Ordovician fossils of Shantung and Liatung. Geol. Surv. Chosen (Korea), Bull., vol. 11, No. 1, 60 pp., 9 pls.
1934. The Cambro-Ordovician formations and faunas of south Chosen. Paleontology. Pt. I. Middle Ordovician faunas. Tokyo Imp. Univ. Fae. Sci., Jour., sec. II, vol. 3, pp. 329-520, pls. 1-44.
1936. On the Stereoplasmoceratide. Japanese Jour. Geol. Geogr., vol. 30, Nos. 3-4, p. 230-242.
Miller, A. K., Dunbar, C. O., and Condra, G. E.
1933. The nautiloid cephalopods of the Pennsylvanian system of the mid-continent region. Nebraska Geol. Surv., ser. 2, Bull. 9. 240 pp., 24 pls., 32 figs.
Miller, A. K. and Furnish, W. M.
1938. Lower Mississippian nautiloid cephalopods of Missouri, Univ. of Missouri Studies, vol. 13, No. 4, pp. 149-178, pls. 38-48.
1940. Studies of Carboniferous ammonoids. Parts I-IV. Jour. Pal., vol. 14, p. 356-377, pls. 45-49.
Ruedemann, R.
1906. Cephalopoda of the Champlain basin. New York State Museum,
Bull. 90, 604 pp., 38 pls., 57 figs. Shimizu, S. and Obata, T.
1935. New Genera of Gotlandian and Ordovician nautiloids. Jour. Shang- hai Sei. Inst., sec. 2, vol. 2, pp. 1-10.
1936. On some new genera of Ordovician nautiloids from east Asia. Shanghai Sci. Inst., Jour., sec. 2, vol. 2, pp. 11-25.
Teichert, C.
1936. (Review of)Shimizu and Obata—New genera of Gotlandian and Ordovician nautiloids. Geolog. Zentralblat, Abt. B, Paleont., Paleont. Zentralbl., Bd. 8, p. 159.
1936. (Review of) Shimizu and Obata—On some new genera of Ordo- vician nautiloids from east Asia. Geol. Zentralbl., Abt. B, Paleont., Paleont. Zentralbl., Bd. 8, p, 372.
1940. Contributions to nautiloid nomenclature. Jour. Pal., vol. 14, p. 590- 597.
Troedsson, T.
1926. On the Middle and Upper Ordovician faunas of northern Green- land. I. Cephalopods. Meddelelser om Gronland, Bd. 71, pp. 1-157, pls. 1-65.
PLATES
The cost of illustrative materials for this series of papers has been met by the Faber Publication Fund of the University of Cincinnati Museum.
PEALE 1 (en)
130 BULLETIN 109 130
HXPLANATION OF PLATE 1 (1)
(Tetrameroceras, Rayonnoceras and Werneroceras)
Figure Page
1. Tetrameroceras faberi Flower, n. sp. i ee 22 Holotype, adoral aspect, venter beneath. Univ. of Cinein- nati Museum, No. 22532. Osgood limestone, Madison, Indi- ana.
2. Rayonnoceras malotti Flower, n. sp. . .... .- = SAB 2 Holotype, a vertical section, oriented with the ventral side beneath as in position of burial, and as shown in text fig.
1. About X2%. Univ. of Cineinnati Museum, No. 24078. Chester group, southern Indiana. (Not fig. 1 as indicated in text.)
3. Werneroceras plebiforme (Hall) — a 2! Se 19
Hypotype. Univ. of Cincinnati Museum, No. 22866. From the uppermost beds of the Union Springs member of the Marcellus, Stockbridge Falls, Oneida Creek, Madison Coun- ty, New York.
132 BULLETIN 109 132 EXPLANATION OF PLATE 2 (2) (Ordovieian and Silurian nautiloids) Figure Page
1-3. Pentameroceras cumingsi Flower, n. sp. ~~~ 2 eS Ob Holotype. Univ. of Cincinnati Museum, No. 23095. 1— adoral, 2—lateral, and 3—ventral views, X 1. Huntington dolomite, Delphi, Indiana.
4. Valecouroceras cyclops Flower, n. sp. 2 Sead Vertical section through center of siphunele, xo Univ. of Cincinnati Museum, No. 24177. Valcour limestone, Little Monty Bay, southeast of Chazy, N. Y.
5-6. Vaicouroceras cyclops Flower, n. sp. _—— : eke a Sections of siphunele, about X2%. 5—adapical end of speci- men ground to show cross section. 6—oblique section from same specimen, attaining the center of the siphuncle ador- ally, but cutting only the margin adapically. Univ. of Cin- cinnati, No. 24178. Valcour limestone, Little Monty Bay, Chazy, New York.
7. Gonioceras hubbardi Flower, n. sp. __~ 226 Holotype, about X14. University of Cincinnati Museum, ‘No. 22846. Chickamauga limestone, north side of Buckeye Mt., Giles County. Virginia.
8. Actinoceras arcuanotum Flower, n. sp. _------. 68
Holotype, Xl. Univ. of Cincinnati Museum, No. 22580. Tyrone limestone, High Bridge, Ky. (Not fig. 7 as indicated in text.)
Buu. AMER. PALEONT. No. 109, Pu. 2
Pu. 2, Vou. 28
SN te gee ect th ieee
me
role
j ~
“) eam : — i
et
ott | -). a a ee ,] a ‘i > an . oo Gt f a he 7 ; As ; A : ae 1 > ¥ . eer f . Za ‘9 a > ow ye ; E i te,
4 ’ ‘ Le i ~ ' H
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" 1 , _
~ fi & 7 ‘4 Pr of * : i ‘ ii ‘ 5 -_ | . ‘
134 3ULLETIN 109 134
[EXPLANATION OF PLATE 3 (3) (Ordovician and Silurian nautiloids)
Figure Page
Holotype, X1, lateral aspect, Univ. of Cincinnati, No. 225 532. : Osgood limestone, Madison, Taterey
Tetrameroceras faberi Flower, n. sp. —~ ss 2795
2-6. Actinemorpha pupa Flower, n. sp. —_~ Breen = 15/5) Holotype, Univ. of Cincinnati Museum, No. 8969. 2—Siph- uncle, ground from ventral side, X2%, 3—4—cross sections from adoral and adapical end of small piece shown near base of living chamber in figs. 4 and 5, — showing siphunele in cross section. 5—ventral aspect, X1 6—lateral aspect, X1, venter on right. Ventral outline lost in grinding, restored in black. Origin uncertain, believed to be Platteville of Wisconsin.
7. Valeoureceras cyclops Flower, n. sp
Cross section of siphuncle, X214. Univ. of Cincinnati Muse- um, No, 24177. Valcour limestone, Little Monty Bay, south-
sast of Chazy, N. Y. (Note—For Gonioceras hubbardi see Plate 2, fig. 7.)
PL. 3, VOL. 28 Buu. AMER. PALEONT. No. 109, Pu. 3
136
Figure
il
7-8.
9-10.
11. Valeouroceras cf. seelyi (Ruedemann)
BULLETIN 109 136
EXPLANATION OF PLATE 4 (4) (Chazyan (Ordovician) nautiloids)
Page
Valcouroceras, sp. 2 wee ee. (5!) Lateral view of an immature ‘fragment. “Univ. of Cinein- nati Museum, No. 24189. Valcour limestone, Little Monty Bay, southeast of Chazy, N. Y.
. Valcouroceras bovinum Flower, n. sp. —---—---__--.___---._. 45
Paratype,Univ. of Cincinnati, Museum, No. 24170. 2—-ven- tral, 3—lateral views. Same horizon and locality.
. Malcouroceras, sp. 10 ee 49
Lateral view of an immature fragment, Univ. of Cincinnati, Museum, No. 24180. Same locality and horizon.
: Walconenecess obesum Flower, 1. .sp= = eee 46
Holotype, lateral aspect, X1, Univ. of Cincinnati Museum, No. 24172. Same locality and horizon.
7) Valcouroceras,, Span pf ar 2 sea 49
Early stage in vertical section, X1, showing slender sub- orthochoanitie siphuncle. Univ. of Cincinnati Museum, No. 24173. Same locality and horizon.
Graciloceras longidomum Flower, n. sp, —-—----- 74 Sections of two fragments of phragmocones, about X24, 7—Retains deep apical chamber. Univ. of Cincinnati Museum,
No. 24183. 8—Paratypes. Univ. of Cincinnati Museum, No. 24184. Upper Chazyan, Little Monty Bay, Chazy, New York.
Valcouroceras bovinum Flower, n sp.. _.. 45 Holotype, X1, 9—lateral, 10—Ventral aspects. Univ. of Cin- cinnati Museum, No. 24169. Same locality and horizon.
Vertical section, X1. Shows siphuncle in stage very close ‘to that of text fig. 1 |g5 Whatidye) iF Cincinnati Museum, No. 24190. Same locality and horizon,
No. 109, Pu. 4
Buu. AMER. PALEONT.
Pu. 4, Vou. 28
138 BULLETIN 109 138 > EXPLANATION OF PLATE 5 (5) - (Paleozoic nautiloids)
Figure Page
1. Archiacoceras subveniricosum (d’Archiac and de Verneuil) 53 Hypctype, Univ. of Cincinnati Museum, No. 22506. Thin eross scetion trough siphunele wall, about X 10, showing structure of connecting ring and rays. Gerolstein, Hifel, Ger- many.
2-3. Eorizoceras platycercides Flower, n. sp. --—. --=—.. - -—- ---- ——— 70 Holotype, X1. 2—lateral 2—ventral (convex) sides. Univ. of Cineinnati Musecm, No. 24186... Valeour limestone, Little Monty Bay, Chazy, New York.
4-5. Trocholites gracilis Flower, n. sp. ---------.— <. 1 81 4—paratype, slightly greater than X1, Univ. of Cincinnati Museum, No. 24192. 5—holotype, slightly greater than xl, Univ. of Cincinnati Museum, No. 24191, Valcour limestone, Little Monty Bay, Chazy, New York.
6-7. Trocholites ruedemanni? Flower, n. Sp. 2a ng Holotype, Univ. of Cincinnati Museum, No. 24193. 6—cross seciion of shell. 7—lateral aspect, one-half of the specimen sectioned longitudinally. Slightly greater than X1. Valeour limestone, Little Monty Bay, Chazy, New York.
8. Centrocyrtoceras mozolai Flower, n. sp. —-------------------__-______ 75 Holotype, lateral aspect, about X2%. Univ. of Cincinnati Museum. No. 24188. Valecour limestone, Little Monty Bay, Chazy, New York.
92 Laureloceras \cumingsi® Flower, 1.) SD. ee 98 Holotype, Univ. of Cincinnaii Museum, No. 24194. 9 — vertical section, enlarged, from adapical portion of type showing suborthocioanitic siphuncle. 12—lateral surface of holotype, somewhat weathered. Laurel limestone, West- port, Indiana.
10=tiheValcouroceras) cyclops Hlowers n. Sp. 47 10—ventral and 11—lateral aspects. Paratype, Univ. of Cincinnati Museum, No. 24179. Valeour limestone, Little Monty Bay, Chazy, New York. (Not figs. 11-12 as indi- cated in the text.)
13-14. Eotripteroceras minutum Flower, n. sp. —. alt
Holotype, Univ. of Cincinnati Museum, No. 24187. 13— apical view; showing septum, with venter oriented to the right. 14—vertical section. Valeour limestone, Little Mon- ty Bay, Chazy, New York. X2%.
i
— =
Pu. 5, VOL. 28 Buu. AMER. PALEONT. No. 109, Pu. 5
PLATE 6 (6)
140
Figure
BULLETIN 109
EXPLANATION OF PLATE 6 (6) (Actinosiphonate cephalopods)
140
Page
1-9. Archiacoceras subventricosum (d’Archiac and de Verneuil)
Sections through siphunele. Univ. of Cincinnati Museum, No. 22506. Gerolstein, Eifel, Germany; Middle Devonian.
1-3. Transverse longitudinal sections through siphuncle.
1—Strongly eecentrie section, cutting septal wall near for- amen, and showing the continuity of the rays near the per- iphery through the greater part of the length of each seg- ment. 2—Section close to center of siphunecle cutting some of the rays obliquely, and showing the rays as appar- ently diserete structures. 3—A second section, not far from that shown in fig. 2, showing annular nature of the rays. Near the top of the figure a ray can be seen which simulates annulosiphonate structure. The rays are repeated segment- ally but are fused. Markings on the figure indicate the position of the cross sections of figs. 4-9. About X1.
4-9. Selected photoegzsaphs taken from a series of serial sections
progressing orad in the shell. 4—Selection showing partial fusion of rays of an adapical and an adoral series, the ad- oral ones appearing on the inside, and not being con- tinuous all around the siphuncle. 5—Farther orad, the adoral series forms a comple-e ring, shown only par- tially here, on the left side, while aligned with rays of the adapical series. 6—Cross_ section essen- tially at region of septal neck. 7—Section still in region of neck, slightly farther orad. 8—Section just orad of septal foramen. The siphunecle enlarges more rapidly orad from the neck on the side farthest from the shell wall. 9—Section farther orad showing condition which is typical up to the adoral end of the segment where a condition like fig. 4 would be encountered.
60
In all sections the shell wall is oriented beneath the siphunele.
In most sections this is more or less completely filled by light calcite, which also occupies the right side of the siphunele as oriented in fig. 4—9. Sections are approximately X2.
XV. (Nos. 55-58). 314 pp., 80 pls. —.._-___--___-.—__-_--__ 6.06 Mainly Bcuadoran, Peruvian and Mexican Tertiary forams and mollusks and Paleozoic fossils.
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ce Fasciolarias and Paleozoic and Recent Hexactinel-
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ae eozoic siphonophores and abnormal Busycons. ye an
SEP 14 19
STITUTION
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BULLETINS OF
AMERICAN PALEONTOLOGY
Vol. 28
No. 110
Three Forks Fauna in the Lost River Range, Idaho
By
Ewart M. Baldwin
September 6, 1943
Paleontological Research Institution Ithaca, New York WES A.
fate FORKS PAUNA IN, THE LOST RIVER RANGE, IDAHO
By Ewart M. Baldwin INTRODUCTION
The Lost River Range forms a prominent topographic unit in south central Idaho. The range trends southeastward across the central portion of the Borah Peak quadrangle toward the Snake River Plains where it is covered by recent volcanics. The area discussed in this paper is confined to the northern half of the range in the Rorah Peak quadrangle (U. S. Geol. Survey topo- graphic sheet, 1932).
During the summer of 1941 and 1942, field work in the Lost River Range disclosed a shaly limestone which contained an abundant fauna in places. This formation was correlated with the Three Forks formation, Three Forks, Montana, on the basis of similarity of faunas.) The Three Forks has not been previously reported in south central Idaho, although Richardson (1913), Piper (1924) and Mansfield (1927) have reported the Three Forks in southwestern Idaho and neighboring regions in Utah.
The Three Forks formation was described by Peale (1893) at Three Forks, Montana. It has been called the Three Forks shale and the Three Forks limestone, depending upon lithology. Berry (1943) redefined the type section and removed an upper yellow sandstone member, which contained a Syringothyris fauna, and proposed the name Sappington sandstone for it. The name Three Forks formation was restricted to the shaly limestone be- tween the Jefferson formation and the Sappington,
4 BuLLETIN 110 144
Previous work on the fauna of the Three Forks has been done by Raymond (1907, 1909, 1912) who discovered the occurrence ~ of certain Upper Devonian ammonoid forms. Haynes (1916) worked out a detailed stratigraphic section and an excellent report on its fauna.
Earlier geologic work in the Lost River Range has been of a broad reconnaissance nature. More detailed work has been done in the neighboring Wood River District and Bayhorse region by Ross (1930, 1937). He summarized the stratigraphy of a thick Paleozoic section in a report on south central Idaho. Although he did not recognize the Three Forks formation, he listed a col- lection from the uppermost Devonian strata at Elbow Canyon, east of Mackay, Idaho, which was collected by Umpleby and Girty and examined by Kindle.’ Kindle (in Umpleby, 1917) re- garded the strata, which contained the following species, “‘as a calcareous facies of the Threeforks shale fauna, although is it not a typical fauna of this horizon.”
Productella, sp. Reticularia, sp. Camarotechia, sp. Spirifer utahensis Schizophoria striatula, var. Spirifer whitneyi australis Meristella cf. M. barrisi Athyris parvula Euomphalus eurekensis
This locality corresponds in stratigraphic position with the Three Forks beds some 30 miles to the northwest in the Borah Peak quadrangle, but several of the above forms were not rec- ognized by the writer in his collections.
Kirk and Cooper (in Cooper et al., 1942) reported the follow- ing locality in the Borah Peak quadangle:
‘“The lower part of the Milligen is shaly and contains species of the Threeforks formation. In a ravine southwest of Freighter Spring, on the east side of Double Spring Canyon .. . Cooper identified the following
species: Cyrtospirifer monticola (Haynes), Camarotoechia ef. C. nordeggi Kindle, globular Athyris, and Cleiothyridina devonica Raymond.’’
145 THREE ForKs FauNA: BALDWIN 5
ACKNOWLEDGMENT
Acknowledgment is made to Dr. K. V. W. Palmer under whose direction the identification of the fauna was made and for suggestions during the preparation of this report. This study was made possible largely through the generous aid from the Charles Pean DeLong Graduate Research Fund of Cornell Uni- versity, for which the writer is gratefully indebted.
SHRWIGRAP EY AND, BAUNAL Lists
A section, about one mile east of Freighter Spring, prob»bl.’ the same locality which was called the “lower part of the Mil- ligen” by Kirk and Cooper, was measured and fossils were col- lected. The section is as follows:
feet Massive limestone containing Productellas and SGiimemertellas: es were ee) ee a ee Pies get neat 2710)
ing Cyrtospirifer, Athyris, and Camarotachia; buff in
COIOE | Ao ee Seen ee ee eee schply wes ceAlese nema tO Shaly limestone ; buff color ; and apparently
(CUMS HU MGKENMON ES 17s sae EA tee ESTOS
310
The Three Forks is a lithologic unit easily separated from the overlying Milligen. No sandy phases were noted nor were any similar limestones found in the alternating shales and sandstones of the Milligen. The abundant fauna of the Three Forks forma- tion stops abruptly at the apparently conformable appearance of sandstone.
The Three Forks is nonresistent and generally covered for considerable distances by talus slopes. However, it is found in places where the dip of the strata is favorable, and for this reason, it is concluded that the Three Forks is usually present. An abundant fauna was not found in many of the exposures of the Three Forks formation. Instead these exposures resembled the
oS
BULLETIN 110 146
lower 195 feet of the measured section. Some of these outcrops examined were in a belt along the mountain front well above Antelope flat and a locality about a mile above the powerhouse on ].ower Cedar Creek near Mackay. Perhaps further search would have disclosed the fauna that is so abundant in the upper part of the formation.
The following collections were made: Locality No. 4. In the upper 115 feet of the measured section, one mile east of Freighter Spring near Dickey, Idaho.
Cyrtospirifer whitneyi (Hall)
C. whitneyi var. an.:masensis (Girty) (contains C. monticola (Haynes) ) Spirifer raymondi Haynes
Camarotechia contracta (Hall)
C. ef. C. shimeri Warren
C. nordeggi Kindle
Leiorhynechus madisonense Haynes
L. madisonense var. gibbosum Haynes
L. ef. L. dunbarense Haynes
L. ef. L. jeffersonense Haynes
L. utahense var. ventricosum Haynes Pugnax, sp.
Produetella, sp.
Produetella ef. P. coloradensis Kindle Athyris vitatta Hall
? Leptodesma chillensis, n. sp. Cleiothyridina devonica Raymond Schuchertella chemungensis var. arctostriata (Hall) Schizophoria striatula var. australis Kindle HKuomphalus, sp.
Cheetetes ?, sp.
‘“Orthoceras’’ ?, sp.
Crinoid fragments
Locality No. 5. East side of Grouse Creek Canyon, about a mile below Mill Creek.
Cyrtospirifer whitneyi var. animasensis (Girty) Schuchertella chemungensis var. arctostriata (Hall) Chetetes ?, sp.
Leiorhynchus, sp.
Locality No. 6. Mountain top northeast of Grouse Creek. The
lower part of the formation.
Camarotechia contracta (Hall) Cyrtospirifer whitneyi var. animasensis (Girty)
147 THREE ForKsS FAUNA: BALDWIN 7
CORRELATION CHART OF THREE FORKS FAUNA
Lost River Range Nev.1Colo.2 Mont.3 Banff! CONROE Dar AST RV 9120 i EA See ea ea ee eae 9) es ete lsa Cowhitmeyl-var. animasensis? ~ ........-.-- ce. ce.sceeeneee--2- SCR Lies Ke Ke ee 2 Ehee se SEP EDS RST TTI DU is i ORES 2 ney PE @enmienmo beech amt COMERA CU) |x foe ee es eee ees ek
C. ef. C. shimeri C. nordeggi ds OR en ein WR re oad ah EL a Leiorhynehus cdunbarense
xX Thi, TRUTAYSVONSTES TI CLA eC ( UNO EL Seo Se Be sD ce ee ee eee xa Heer otep lies) GIbCTSONCOSGun a. . a. eke ie eee es ee ela SARs. odes. eRe ks Bele: FERRITE OUAONCTING temree sce. fs feet oy green. SeAN ML LOR ee Oe ee eke ee ees eM ACISONCHSG ives 1D WOSUM) «22 es ee oe Sees ees eee Giaeee LEE ae a | ee SR ee NT ce Sense NO DA EY Big ee oe Siete Broductella tc. Ps coloradensis; 22 See Ke Ke KE clear Z:AIRTEASVATRTUSS, w AVES NLITEE Wh Uap Se wns ae eh CP NN SE eee SMe ie we ener Bagh Ls. PPE HLOdesmanC hill eASIS, MM ASP caee- os ter ene ee Ses est SE eee (Clkenioreingyaemicintnyss GWG OHOIKCRY (ee 5 ene eects sees ere eese ce eeesee sCeeeecee Swe keke Bh. ees Schuchertella chemungensis var. arctostriata _ Sie 5 ae WS cae Me islet Schizophoria striatula var. australis ......_......-.-.--.:--: Sik See Kae POX eee Shaan BYE OND VEU SS SRS 1) Spee eee ee ee me ee ee Shee S s?
1. Devils Gate formation, Nevada, Merriam (1940)
2. Ouray formation, Colorado, Girty (1900); Kindle (1909)
3. Three Forks formation, Montana, Raymond (1907; 1909) (1916)
Banff, Upper Minnewanka formation, Warren (1927)
Identical forms.
Related forms
Includes Cyrtospirifer monticola (Haynes)
CORRELATION
and Haynes
RSS
The Three Forks formation in Idaho is at the top of the known Devonian. In this respect it is similar to Upper Devonian for- mations of the so-called “Cyrtospirifer zone’’, with whose faunas comparisons are made on the above chart.
A close correlation with the restricted Three Forks formation, Montana, is firmly established by a large number of species in common.
However, several striking differences were noted. Cama- rotechia nordeggi Kindle, C. cf. shimeri Warren, Athyiis vitatta Hall, and Pugnax, sp., are several of the forms which are abun- dant in the Lost River Range and unreported from the Three Forks, Montana area. The Camarotoechias have been reported from the Upper Devonian formations in the Canadian Rockies by Kindle (1924) and Warren (1927, 1937). They are associated in the Lost River Range with the abundant Leiorhynchus assem- blage which is prominent in the type Three Forks section, A form which resembles A. citatta, but identified as Meristella
8 BuLLETIN 110 148
barrisi Hall, is rare in the Montana section. The forms are sim- ‘ar in external features and it is probable that the specimens from Montana and Idaho are the same species.
The type Three Forks area contains an ammonoid fauna, a large pelecypod fauna, and numerous specimens identified as Rhipidomella vanuxemi Hall? Although ammonoids were not found in the Lost River Range, it is possible that they will prove to be present. Several poorly preserved pelecypods were noted in the field, and although only one form was collected, a larger fauna is probably present. Haynes (1916) doubtfully assigned numerous specimens to Rhipidomella vanuxenu. They were present in both the upper sandy portion which contained the Syringothyris fauna and in the Three Forks (restricted). Al- though the Syringothyris horizon was not recognized in the Lost River Range, no Rhipidomellas were found in the lower horizons.
The forms which are most numerous in the Three Forks of the Lost River Range are: Cyrtospirifer whitney var. animasensis (Girty), Leiorhynchus madisonense var. gibbosum Haynes, Cieiothyridina devonica Raymond, Athyris vitatta Hall, Pugnax, sp., Camarotechia nordeggi Kindle, and Productellas.
Schindewolf (1934) pointed out that the occurrence of Platy- clymenia americana and P. polypleura, at Three Forks, Montana indicated an affinity with the “Prolobites-Platyclymenia-Stufe” third from the base ammonoid zone of the European Upper Devonian, Miller (1938) correlated the ‘“Prolobites-Platycly- menia-Stufe” with the Connewango ( “possibly only the lower part” ). The Conewango is placed in the lower Bradfordian by Schtchent(1943,).
Cooper (1942, p. 1785) pointed out the apparent relationship of the Three Forks with the Ouray as follows:
‘‘In the Threeforks proper occur a variety of fossils including large Cyrtospirifer, Productella, and Leiorhynchus suggesting affinity ath ihe Percha shale of New Mexico and the Ouray limestone of Colorado. The peleecypods and goniatites . . . indicate a somewhat older age. Of the
former the most important is Loxopteria which in New York is restricted to the Canadaway group.
On the basis of ammonoids, Cooper (p. 1785) placed the Three Forks in the Conneaut group of the Cassadaga stage.
149 THREE ForKS FAUNA: BALDWIN 9
The correlation between the Three Forks formation and the upper Devils Gate formation of Nevada is pointed out by Merriam (1940, p. 62) as follows:
‘*Forms showing a marked similarity are above all the abundantly oe- curring cyrtospirifer and Leiorhynchus. Other analogies are noted (1) In the common occurrence of similar types of Productella, (2) presene> of related forms of Schizophoria, though the species appear to be distinct, (8) occurrence in both faunas of schuchertellas of similar character, (4) absence cr scarcity of Atrypa.’’
The Three Forks may be younger than the upper Devils Gate because in the Lost River Range the moderately thick Grand View dolomite lies between the Jefferson, which contains Pechyphyllum, and the “Cyrtospirifer zone” of the Three Forks formation.
The relationship between the Idaho Three Forks and the upper Devils Gate is more general than specific for although there is a generic similarity, few of the species are in common as is the case with the Lost River Range and the type Three Forks area.
The Exshaw shale in the Canadian Rockies is tentatively correlated by Warren (1937) with the Three Forks formation in Montana, and by Cooper (1942) with the lower part of the “Milligen formation” (Three Forks formation) of the Lost River Kange.
In conclusion, a correlation of the shaly limestone in the Lost River Range with the Three Forks formation of Montana appears to be justified, nct only on the basis of lithology and stratigraphic position, but on the basis of a close similarity in faunal content.
DESCRIPTION OE FOSSILS
Type and figured specimens have been deposited in the Pale- ontological Research Institution, Ithaca, New York. A dupli- cate collection is located in the paleontology laboratory, Cornell University.
The material described and figured in the following pages are all from localities in the Three Forks formation, Upper Devonian of Idaho,
10 BULLETIN 110 150
PHYLUM BRACHIOPODA Genus SCHUCHERTELLA Girty
Schuchertella chemungensis var. arctostriata (Hall) Plate 1, fig. 21
Streptorhynchus chemungensis var. arctostriata Hall, (1867, Pal Nea
vol. 4, pl. 9, figs. 1-12.
Specimens are common in the Three Forks formation. The usual size of shell is 32 mm. in width and 25 mm. in length. Fine intercalary plications are between fine plications which reach the length of the shell.
Locality— Nos. 4 and 5.
Genus CAMAROTCECHIA Hall and Clarke
Camaretechia contracta (Hall) Plate 1, figs. 11, 12 Atrypa contracta Hall, 1843, Geol. N. Y., Rept. of Fourth Dist., p. 66, figs. 2, 3.
Camarotoechia contracta (Hall) Hall and Clarke, 1893, Pal. N. Y., vol. Vili get. lt sp. 192) plod nes: 2o-ac.p4o-
The figured specimen is from the lower part of the Three Forks formation, and is slightly larger and more gibbous than specimens found in the shaly limestone members in the upper part of the formation at locality No. 4.
The specimens compare in description with C. contracta col- lected by Raymond (1909, p. 142, pl. 3, figs. 1-7) but tend to be smaller,
Locality—Nos. 4 and 6. Figured specimen is from No. 6.
Camarotechia nordeggi Kindle Plate 1, figs. 15-17, 22
Camarotoechia nordeggi Kindle, 1924, Pan-Am. Geol., vol. 42, No. 3, p. 128, pl. 14, figs. 4-7.
The specimens are gibbous, and have from 40 to 72 fine
plications which extend from umbo to commissure. The sinus is variable, but deep in the larger specimens. The number of plications appears to depend upon the size of the specimens.
Of 24 measured specimens, the average size is 24 mm. in width, 21 mm. in length, and 15 mm. in thickness.
Locality.—_No. 4 Camarotechia cf. shimeri Warren Plate 1, fig. 10
Camarotoechia shimerit Warren, 1927, Geol. Survey Canada, Mem. 153, Pa o2, Dla A hiosh Ds 1G:
Specimens referred to C. shimeri are smaller than those iden- tified as C. nordeggi Kindle. They have a shallow sinus and have a smaller number of similar fine plications.
There is no sharp break between the characters of the speci- umens and there is a possibility that those referred to C. shimeri
151 THREE ForKS FAUNA: BALDWIN 11
a e€ immature specimens of C. nordegdi. Locality.—No. 4.
Genus LEIORHYNCHUS Hall
Leiorhynchus cf. dunbarense Haynes Plate 1, figs. 3-5
Leiorhynchus dunbarense Haynes, 1916, Ann. Carnegie Mus., vol. 10, pp.
38, 39, pl. 8, fig. 8.
Of six specimens collected, three undamaged individuals average 19 mm. in width, 13 mm. in height, and 13 mm. in thickness. Five specimens have three angular sharp plications on the fold and two rounded plications in the sinus. One has two plications on the fold and one in the sinus. Concentric growth lines are prominent.
L. dunbarense, as figured by Haynes (plate 8, fig. 8), contains three rounded plications in the sinus and does not seem to be typ- ical of the species as he described it. Those specimens from the Lost River Range compare closely with the description, but tend to be smaller, more gibbous, and have less width in proportion to height and thickness.
Locality.—No. 4.
Leiorhynchus madisonense var. gibbosum Haynes Plate 1, fig. 13
Leiorhynchus madisonense var. gibbosum Haynes, 1916, Ann. Carnegie Mus., pp. 39, 40, pl. 7, figs. 14-16.
Cf. Leiorhynchus athabascense Kindle, 1924, Pan-Am. Geol., vol. 42, pp. 217, 218, pl. 14, figs. 1-3.
Cf. Leiorhynchus walcotti Merriam, 1940, Geol. Soc. Am., Spee. Paper, No. 25, p. 82, pl. 9, figs. 4-8.
The pedicle valve is gibbous with a deep flattened sinus which becomes strongly curved toward the front of the shell. Brachial valve is more convex and has a broad, flattened mesial fold which becomes more accentuated toward the commissure,
About five plications are present on the fold and in the sinus. Shells are commonly 25 mm, in width, 18 mm. in length, and 19 mm. in thickness. Plications are indistinct on the lateral slopes.
L. madisonense var. gibbosum differs from L. athabascense in that it does not have the wedge-shaped lateral margins of the latter ; otherwise there is a very strong resemblance. L. walcotti has more angular plications and in addition it has plications on the lateral slopes; otherwise, though, it corresponds in general shape.
Locality.— No. 4.
12 BULLETIN 110 152
Genus PUGNAX Hall and Clarke Pugnax, sp. Plate 1, figs. 18-20
Cf. Pugnawx altus (Calvin) Hall and Clarke 1893, N. Y., vol. VIII, pt. LI, pl. 60, figs. 1-5. .
Cf. Pugnax pugnus (Martin) Hall and Clarke 1893, N. Y., vol. VIII, pt. II, pl. 60, figs. 6-10. as
Cf. Pugnax minutus Warren, 1927, Geol. Sur. Canada, Mem., 153, p. 99, pl. 4, figs. 2-4.
The average dimensions of over 50 specimens is approximately 14 mm. in width, 9 mm, in leagth, and 11 mm. in thickness, Gen- erally two to three round, to subangular plications, which carry through to the umbo, are on the fold and one to two rounded plications are in the sinus. There is some variation in the depth of the sinus which begins about midlength of the shell and usual- ly becomes deeply accentuated at the commissure. The lateral slopes are usually smooth but occasionally faint plications can be found.
The specimens resemble P. altus in trigonal outline and depth of sinus, but they are smoother on the lateral slopes. There is less resemblance to P. pugnus for the sinus of the specimens is deeper in proportion, and the lateral slopes are smoother. The specimens are universally larger than P. minutus, the sinus is deeper, and the plications reach the length of the shell, whereas they do not in P. minutus.
There is a possibility that the specimens from the Lost River Range, Idaho, represent a new species of Pugnax.
Locality.—No. 4.
Genus CYRTOSPIRIFER Nalivkin Cyrtospirifer whitneyi var. animasensis (Girty) Plate 1) firs 65 a4 Spirifer disjunctus var. animasensis Girty, 1900, 20th Ann. Rep., U. 8S. Geol. Survey, Pt. 2, pp. 48-55, pl. 4, figs. 1-10. Spirifer whitneyi var. animasensis Kindle, 1909, U. 8. Geol. Survey, Bull. 391. pp. 25, 26, pl. 9, figs. 1-3a. Spirifer whitneyt var. monticola Haynes, 1916, Ann. Carnegie Mus., vol. 10, pp. 36-38, pl. 4, figs. 6-10; jolla {G5 amass dle g(a
Cyrtospirifer forms are common in the Upper Devonian of the Rocky Mountain region, Girty reported them from the Ouray District, Kindle from Colorado and New Mexico, Haynes from Three Forks, Montana, and Merriam (1940) from Nevada.
Girty, when studying the fauna of the Ouray District, Colora- do, identified a form as Spirifer disjunctus var. animasensis.
153 THREE ForKS FAUNA: BALDWIN 13
Kindle, when restudying the area and New Mexico, concluded that these forms were more like Cyrtospirifer whitney (Hall) because of the radiating pattern on their plications. Although he noted differences in size and shape, he concluded that because of the variability of the C. disjwnctus type, it would be inadvisable to create a new species. He did, however, restrict S. whitneyt var. animasensis to the smaller specimens with the high cardinal area and identified the rest as S. whitney.
Haynes, when studying the Three Forks, Montana area, found Cyrtospirifers which he concluded were identical with forms from Colorado identified as S. whitneyi by Kindle. He noted the differences enumerated by Kindle and considered them sufficient to name the new variety, S. whitney: var. monticola. He des- ignated as types seven specimens which showed a continuous variation in shape of the cardinal area from those with a narrow hinge line and incurved beak, to those with a wide, high cardinal area and straight beak. The latter are difficult to separate from C. whitneyi var. animasensis (Kindle).
Over 50 specimens of Cyrtospirifers were collected by the writer in the Lost River Range, Idaho. Their average dimen- sions were 32 mm. in width, 25 mm. in length, or a ratio of about 1: .8. Most of the specimens were insufficiently preserved to show the surface markings, but the cardinal area varied within the limits of C. whitneyi var. monticola as was shown by direct comparison with the type specimens.
Comparison of the Cyrtospirifers from the Lost River Range, Idaho, was also made with a large collection obtained near Glen- wood Springs, Colorado, by W. C. MacQuown. The Colorado specimens are similar in detail but larger than usual, and it ap- pears that size, like shape of the cardinal area, may be variable in this form of Cyrtospirifer .
Because these forms of Cyrtospirifer cannot be conveniently separated on size, as did Kindle (1909), and because variability of cardinal area has been demonstrated by Haynes (1916), Mac- ©uown! proposed that the name, C. whitneyi var. animasensis
1Unpublished thesis, Cornell University, 1943.
14 BULLETIN 110 lot
(Gitty) be extended to include C. whitneyi var. monticola (Haynes) and the larger forms from Colorado which were iden- tified 2s S. whitneyi by Kindle. The writer agrees with this classification.
Locality—wNos. 4, 5, and 6.
Genus SPIRIFER Sowerby Spirifer raymondi Haynes Plate 1, fig. 23 Spirifer raymondi Haynes, 1916, Ann. Carnegie Mus., vol. 10, pp. 31-33, pled, figs: I-2-) pls6, hes. 12) 13:
Several small specimens were collected. The best specimen, which is figured, is 28 mm, in width, 16 mm. in length, and II mm. in thickness. Specimens have a straight narrow hinge line and well-defined fold and sinus.
Locality—No. 4.
Genus ATHYRIS McCoy Athyris vitatta Hall Plate 1, figs. 8, 9 Athyris vitatta Hall, 1867, Geol. Sur. N. Y., vol. 4, Pt. 1, pp. 289, 290, pl. 46, figs. 1-4.
Athyris vitatta Hall, Grabau, 1933, Pal. Sinica, p. 508, pl. 43, figs. 10 a-d.
The average size of 50 specimens is approximately 16 mm. in width, 17 mm. in length, and 13 mm. in thickness. Specimens show a deep sinus with a prominent fold on either side. Fine concentric growth striae are present. Some specimens show greater width than length.
They resemble A. angelicoides Merriam, but have a sharper, more upright beak and are less gibbous. They resemble A. an- gelica Hall in shape, but are uniformly smaller. Forms which resemble A. vitatta have been identified as Meristella barrisi Hall in the “Cyrtospirifer zone” in Colorado and New Mexico, (Kin- dle, 1909) and from Elbow Canyon in the Lost River Range (Kindle in Umpleby, 1917).
Locality.—No. 4.
Genus CLEIOTHYRIDINA Buckman Cleiothyridina devonica Raymond Plate 1, fig. 14
Cleiothyridina devonica Raymond, 1909, Ann. Carnegie Mus., vol. 5, Nos. 2, 3, pp» 143, 144) pl. 3; figs. 16, 17; pl. 4, fies. 1-11.
Cleiothyridina devonica is common in the upper part of the Three Vorks formation. It resembles lthyris coloradoensis Girty, but is smaller in size.
Locality —No. 4.
155 THREE ForKS FAUNA: BALDWIN 15
PHYLUM MOLLUSCA CLASS PELECYPODA Genus LEPTODESMA Hall ? Leptedesma chillensis, n. sp. Plate 1, figs. 1-2
Two left valves of a new species of a long inequivalve pelecy- pod were collected in the upper part of the Three Forks forma- tion. The larger and more mature specimen (fig. 1) is hereby designated as the holotype (Pal. Res. Inst, No. 6048) and the smaller specimen, (fig. 2) is the paratype (Pal. Res. Inst., No., 6049).
The specimens show a short anterior and a long posterior end and an alignment of the valve very nearly parallel to the hinge line. The larger specimen is incomplete, but corresponds to the smaller specimen in detail. In the larger specimen there is a narrow rounded beak which extends slightly over the hinge line but flattens out and broadens toward the posterior end. There is a shallow depression between the hinge line and the rounded part of the valve along the posterior part. The shell is covered by con- centric growth lines.
The specimens resemble species of Leptodesma in many re- spects, but differ in being aligned nearly parallel to the hinge line so that no posterior wing is developed. They are therefore questionably assigned to Leptodesma.
Locality.—No. 4.
REFERENCES
Berry, G. W. 1943. Stratigraphy and structure at Three Forks, Montana, Geol. Soe. Am. Bull., vol. 54, pp. 1-30. Cooper, G.A ., et al. 1942. Correlation of the Devonian sedimentary formations of North America. Geol. Soc. Am., Bull., vol. 53, pp. 1729-1794. Girty, G. H. 1900. Devonian fossils from southwestern Colorado. U. 8. Geol. Sur- vey, 20th Ann. Rep., pt. 2, pp. 31-81, pl. 7. Haynes, W. P. 1916. The fauna of the Upper Devonian in Montana. Ann. Carnegie Mus., vol. 10, pp. 13-54, pl. 4. Kindle, E. M. 1908. The fauna and stratigraphy of the Jefferson limestone in the northern Rocky Mountain region. Bull. Amer. Paleont., vol. 4, No. 20, pp. 1-39, 4 pl.
16 BULLETIN 110 156
1909. The Devonian fauna of the Ouray limestone. U. 8. Geol. Survey Bull, 3915 pp: 1-80, 10 pl.
1924, Three new Devonie fossils from Alberta. Pan-Am. Geologist, vol. 42, pp. 217-218, pl. 1.
Mansfield, G. R.
1927. Geography, geology, and mineral resources of part of southeast-
ern Idaho. U.S. Geol. Survey, Prof. Paper 152, pp. 1-453. Merriam, C. W.
1940. Devonian stratigraphy and paleontology of the Roberts Moun- tains region, Nevada. Geol. Soe. Am., Spec. Paper 25, pp. 1-114, pls. 16.
Miller, A. K.
1928. Devonian ammonoids of America. Geol. Soc. Am., Spee. Paper
14 pp. 1-262, pls. 39, figs. 41. Peale, A. C.
1893. The Paleozoic section in the vicinity of Three Forks, Moniana.
U. S. Geol. Survey, Bull., 110, pp. 1-56. Piper, A. M.
1924. Possivilities of petroleum in Power and Oneida counties, Idaho.
Idaho Bur. Mines and Geology, Pamph., 12, pp. 1-24. Raymond, P. E.
1907. On the ceccurrence, in the Rocky Mountains, of an Upper De- vonian fauna with Clymenia. Am. Jour. Sei., 4th ser., vol. 23, pp. VVNG-122), figs I.
1909. The fauna of the Upper Devonian in Montana. Ann. Carnegie Mus., vol. 5, No. 2, 3, pp. 141-158, pl. 6, fig. 6.
1912. The Clymenia fauna in the American Devonian. 7th. Internat. Zool. Cong., Pr., pp. 1-4.
Richardson, G. B.
1913. The Paleozoic section in northern Utah. Am. Jour. Sci., 4th ser.,
vol. 36, pp. 408-416. Ross, C. P.
1930. (Umpleby, Westgate and Ross) Geology and ore deposits of the Wood River region, Idaho. U. 8. Geol. Survey, Bull. 814, pp. 1-250.
1934. Correlation and interpretation of Paleozoic stratigraphy in south- central Idaho. Geol. Soe. Am., Bull., vol. 45, pp. 937-1000.
1937. Geology and ore deposits of the Bayshore region, Custer County, Idaho. U. 8. Geol. Survey, Bull., 877, pp. 1-161.
Schindewolf, O. H.
1934. Ueber eine. oberdevonische Ammoneen-Fauna aus den Rocky Mountains. Neues Jahrb., Beilage-Band 72, Abt. B, Heft 3, pp. 331- 350. ;
Schuchert, Charles
1943. Stratigraphy of the eastern and central United States. John
Wiley & Sons, New York, 1013 pp. Umpleby, J. B.
1917. Geology and ore deposits of the Mackay region, Idaho. U. 8.
Geol. Survey, Prof. Paper 97, pp. 1-129. Warren, P. S.
1927. Banff area, Alberta. Geol. Survey Canada, Mem. 153., pp. 1-94.
1937. Age of the Exshaw shale in the Canadian Rockies. Am. Jour. Sci., 5th ser., vol. 33, p. 454-457.
PLATE
PLATE 1 (7)
is Buuietin 110 58 I3PLANATION OF PLATE 1 (7) Figure Page 1-2. ? Leptodesma chillensis, n. sp. ar : 1s Figure 1 is sligitly enlarged. Holotype, Pal. Res. Inst., No. 6048. Figure 2, paratype; x 3; Pal. Res. Inst. No. 6049. 3-5. Leiorhynchus cf. dunbarense Haynes i: Width, 18 mm.; leng: i, 13 mm.; thickness, 12 mm. Pal. Res. Inst., No. 6041. 6-7. Cyrtospirifer whitneyi var. animus nsis Cirty 12 Width, 35 mm: leno ti e25) nim; tiicdkvess, lS om) Peleies: Inst., No. 6044. 8-9. Athyris vitatta Hall ee 14 Width, 17 mm.; length, 16 mm.; thickness, 10 mm. Pal. Res. Inst., No. 6046. 10. Camaroteechia cf. shimeri Warren alt) Width, 22 mm.; length, 18 mm.; t!ickness 5 mm.. Pal. Res. Inst., No. 6040. 11-12. Camarcteechia contracta Hall : aoe eee 310, Width, 10 mm.; length, 8 mm.; thickness, 4 mm. Pal. Res. Inst., No. 6037. 13. Leiorhynchus madisonense var. gibbosum Haynes + S15}; Width. 24 mm.; length, 17 mm.; thickness 17 mm. Pal Res. Inst. No. 6042. 14. Cleiothyridina devonica Raymond Sep i : 14 Width, 14 mm.; length, 12 mm.; thickness, 5 mm. Pal. Res. Inst., No. 6047. 15-17. Camarctechia nordeggi Kindle ey 1a Sa en erent 3l()) Width, 20 mm.; length, 16 mm.; thickness, 10 mm. Pal. Res. Inst., No. 60388. 18-20. Pugnax, sp. Sac 8 ac es A ene 12 Width, 18 mm.; length, 9 mm.; thickness, 10 mm. Pal. Res. Inst., No. 6043. 21. Schuchertella chemungensis var. arctostriata Hall = 10 Width, 32 mm.; length, 25 mm. Pal. Res. Inst., No. 6036. 22. Camarotechia nordeggi Kindle pa ee Aa ws Le 10 Width, 29 mm.; length, 27 mm.; thickness, 18 mm.; more gibbous and larger than usual. Pal. Res. Inst., No. 6039. 23. Spirifer raymondi Haynes ____ 14
Width, 26 mm.; length, 16 mm. ; ‘thickness, 11 mm. Pal. Res. Inst., No. 6045.
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BULLETINS OF
AMERICAN PALEONTOLOGY
Now TE
Contributions to the Paleontology of
Northern Peru
Part VII. The Cretaceous of the Paita Region By
A. A. Olsson
January 6, 1944
PALEONTOLOGICAL RESEARCH INSTITUTION ItHaca, NEw York
UES. VAC
CONTENTS
Page Foreword ...... Tol RANG. 2c eee te OSE TE, Be) Oh ae PTE RUE PPR AR PEER Tree a 5) FEran(T AGS UNL a 1 ee el aE Sterile ees eee eS i Be T Oey en ie aR ne gue nk Re ED RAO ERE SE cps 8 Hpnombralte ,CREHACEOUS: <2) cto Ber meet: 0! Bere i) es Rac cvonesaneeeee 12 Fossils from the Monte Grande and Paita Upper Senonian ........ 16 Promo taser atbal | Ore tare ous) s2 see ese erecta eee cae esae ee 19 Related marine equivalents of the Peruvian Upper Senonian in South sNsrrerneR. AGL VIE Tobe TREY 22 Cle ee) ee a ee ee te er Oe ero 22 Re yl cpetilod Tiara lem VACNIG ZAG elm yet eee. ee Pane ie! es awn son aes eee 24 FEDS wala hse Se Senet RI OR leek eae he erm Nn tne pM 25 fearmincmonot@uraenon ter. ne. see Ask ole ah ek ok ee 25 Li TERDGEY «oso a A eR bert PEE Cee 26 COUGLRENE DORSEY peta ee al lo ied es i ee re eM nk te 27 TRESUETRND glen Ne eae a ape oe ae bee. ay Nine oh Oren Se 28 IB tb no oral lniypa eee seesees eee eee Me 9 ieee SM! ID Nn | Re ieee thc eer ar aee Nne ANC 28 S SHAR DIED SEY (SY Oren OS KONTO se ee ne eee eres eee 31
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CONTRIBUTIONS 1O: THE “PALEONTOLOGY OF NORTHERN PERU: PART VII THE CRETACEOUS OF THE PAITA REGION
By
A. A. OLsSson
FOREWORD
The principal purpose of this paper is the description and illus- tration of some Upper Senonian molluscan fossils from the Paita region of northwestern Peru. It supplements therefore to some ex- tent our earlier contributions to the Cretaceous of the Amotape region, a short distance further to the north. Our collections were obtained mainly in 1937 and 1938 when several short recon- naissance trips were made to the localities along the south side of the Paita Mountains for Cretaceous fossils, first described by Gerth. I am deeply grateful to Mr. O. C. Wheeler, Chief Geol- ogist for the International Petroleum Company, Toronto and to Mr. O. D. Boggs, formerly Chief Geologist in Peru, who ac- companied me on these trips, for their most generous assistance in the field studies and in collecting.
As the Peruvian fauna differs so greatly from any other Cretaceous assemblage yet described from South America, it has been necessary to propose many new generic and subgeneric names for some species. These names are the following:
Genus Sechuritella Type, S. terebracincta, n. sp. Genus Trocotaulax Type, T. elegans, n. sp.
6 Buuuetin 111 164
Genus Thianassa Genus Rhinotamides (Genus Sympanotomus Genus Nodifaunus Genus Glorioclava Genus Previcarya Genus Tortucerithium (cenus Parinana
(;enus Torgnellus
(;eaus Perustrombus Subgenus Orthostrombus Genus Peruarca
(cenus Incanopsis
Subgenus Tortucardia
Subgenus Perucardia Subgenus Incacardium
Subgenus Sechurina
Genus Mulinoides (genus Macrodonax
Subgenus Tellipiura
Subgenus Austrosphenodiscus
Genus Paciceras
Type; U2 ciconia, 1. sp: Types Re qudis,m:sp: ype, S. imiUncakis; maasm Type, N. nodosa, n. sp. Type, G: inca, n> sp: Type, P. peruviana, n. sp. ype, i textilis;anessp: Type, Morgana magma Woods (Eocene) Type, T. peruvianus, n. sp. iype. Po wheeler, meisp: Type, Perustrombus to1rtu- gensis, n. Sp. Type, P. pectunculoides, n. sp. Type, I. acariformis, n. sp. Type, Glossocardia — ste phen- soni, n. Sp. Type, Cardium bruggeni, n. sp. Type, Cardium mellisum, n. sp. Type, Aphrodina australis, Me Sp: Type, Mulinoides chilca, n. sp. Type, Macrodonax peruviana, n. sp. Type, Tellidora peruana, n. sp. Type, Coahuilites peruviana Gerth Types. paciicasnsssp:
I am using this occasion to change two, earlier generic names
given to Peruvian fossils which have proved to be preoccupied:
Peruvia Olsson, 1934 changed to Peruviella, new name. Preoeeupied by Peruvia Mallock, 1929 in Diptera, Ann. Mag. Nat. Hist.
(10) 4, 104.
Iddingsia Olsson, 1929, changed to Iddingsella, new name. Preoeeupied by Iddingsia Walcott, 1924 in Trilobita, Smith. Mise. Coll.
5, 58. Gloversville, N. Y. Aug. Ist, 1943.
165 CRETACEOUS OF PAITA: OLSSON if
INTRODUCTION
The discovery of Upper Cretaceous beds with rudistids and Roudaireia at Monte Grande near Negritos in northwestern Peru was first announced by Iddings and Olsson(1) in 1928. This was followed by Gerth’s (2) description of a small Upper Cretaceous fauna with rudistids, Sphenodiscus and other mollusks from exposures along the south side of the Paita Peninsula. These two localities have thus far furnished the only Upper Cretaceous or Maestrichtian molluscan fossils yet known in coast- al Peru. Aside from these occurrences, the only other important development of late Cretaceous deposits along the west coast of South America are the fossiliferous beds on the island of Quiri- quina and around the shores of the Bay of Concepcion on the coast of Chile. The Quiriquina beds have assumed importance in geological literature through their early discovery and descrip- tion in the writings of D’Orbigny and Darwin(3). The Chilian de- posits and those of northern Peru were formed in relatively small, local embayments which barely touched the present coast. This late Cretaceous and purely Pacific transgression(4) was therefore completely distinct from the great Tethyan or Mediterranean in- vasions which flooded the earlier Cretaceous geosynclines within the Andes proper. In Venezuela, and more especially in Co- lombia, the Maestrichtian sea persisted for a time longer within the mountain zone although, except locally or in restricted hor- izons, its deposits are nonmarine and coal-bearing. The restric- tion of the Peruvian marine Upper Senonian to the coastal zone and its predominantly, coarsely clastic character is strong evi- dence of regional uplift towards the close of the Cretaceous period. This phase in the formation of the Peruvian Andes, only one of many, thus corresponds closely in time to the Laramide revolu- tion of North America as pointed out by Steinmann, Stille(5) and many other students of South American geology.
8 BuLuETIN 111 166
GEOLOGY
The region referred to in this paper as the Paita Peninsula is a portion of the northwest coast of Peru between 5° 4’ and 5° 20' S. Lat. and lying between Paita Bay on the north and the Bay of Sechura on the south. In contrast with the smoothly curving shores and the sandy beaches of these deep bays, the coast line of the Paita Peninsula is very irregular, its jagged headlands and rocky islands being formed of hard, metamorphic and crystalline rocks of great complexity of structure and composition. This very great contrast in coastal development has resulted primarily from the condition that the Paita Peninsula is part of an old range of mountains which became dismembered by faulting in the Late Cretaceous and early Eocene times.
The geology of the Paita Peninsula is little known and has received but scant mention in the literature. Its principal rocks are slates, schists, gneisses or granites which form most of the Paita Mountains and the headlands along the coast at Punta Nermete and Foca Island. These formations were long believed to be Archean but a few Carboniferous rocks found near Paita, show that they are at least partly Carboniferous in age. A rich and varied Permo-Carboniferous fauna has also been known from the Amotapes for many years. It seems probable that the Paita Peninsula was once connected with the Amotape Range to the north of the Chira Valley and with the similar out-lying Cerros de Ilescas and the Lobos Islands to the south. These groups of present-day mountains are composed of essentially similar rocks and their prevailing structural trends, if extended, would join to form a continuous range, Large areas in the east- ern and central part of the peninsula have no rock outcrop, the generally flat, barren surface being floored by young, marine terrace deposits or by drifting desert sands. These level, uplifted, marine plains of deposition have a very extensive development in the coastal region of northern Peru where they are known as tablazos. In the Paita region, this tablazo plain has a mean elevaticn of about 200 feet but it lowers steadily southward into the Sechura desert. The Paita tablazo is formed principally of beach sands and gravels, marine marls and shell limestones which
167 CRETACEOUS OF PAITA: OLSSON 9
locally may reach a thickness of 200 feet. Elsewhere these tablazo deposits may be very thin or entirely missing, the flat floor, generally on rock, being then the peneplained surface or uplifted sea-bottom of the tablazo sea.
Tertiary formations of Eocene, Oligocene and Miocene ages are found at several places in the Paita region. At the city of Paita, the Oligocene Chira shales form the lower pait of the high, tablazo cliffs bordering Paita Bay. They are mainly black shales, weathering light-brown or chocolate color. Fossils are princi- paily pteropods, Foraminifera and thin-shelled mollusks, In- teresting exposures of Eocene rocks occur at several places, their principal area of development being found at Yasila and Jaquay Cunas on the coast between Foca Island and Nermete Point. These names refer to small, fishing camps, the nearby coves affording anchorage and some protection from the heavy ocean swell. At Yasila, the Eocene formations rest directly upon the crystalline basement. These slivers of Eocene sediments occur as small segments between faults which normally trend about N. 50° E. Cross faults are also present but of lesser importance. Aside from the richly fossiliferous character of these Eocene horizons, the Yasila and Paita sections give much interesting in- formation as to the depositional history of Eocene times in north- en Peru. The section at Yasila and Jaquay Cunas is as fol- lows:
Talara Mostly shale Talara shale Basal sandstone.
Chocolate shales and gredas Salina Fossiliferous coneretionary sandstones Basal sandstones and conglomerates
Paleozoie or older Slates, schists, ete.
No rocks corresponding to the lower Eocene or Negritos for- mation have been found in the Paita region, the basement floor at Yasila being overlain by beds containing a Salina or lower nidcle Eocene fauna. The lower 50 to 100 feet of this section 1s composed of barren sandstones and conglomerates, the bed in contact with the basement being generally a coarse breccia
10 BULLETIN 111 168
formed entirely of slate and quartz fragments. Overlying these basal beds are 50 feet or more of highly fossiliferous, concretion- ary shaly sandstones containing Surcula (Andicula) occidentalis, Peruluta peruviana, Pseudoglauconia lissoni, Boggsia anceps and many others. The chocolate shales which overlie the fossil beds are usually unfossiliferous and may be partly Pale Greda in age. Rocks of Salina age have not been found further south so the occurrence at Yasila along the north and west side of the Amo- tape-Paita Range may mark the southern shoreline of the mid- Eocene sea.
The Talaran or lower upper Eocene comprises two members, a lower zone (approximately 200 feet thick) of concretionary, bluish sandstones and an upper shale member. The lower sand- stones are richly fossiliferous and have yielded a large fauna of small mollusks. The concretions contain pieces of fossil wood and are generally thickly seamed with calcite veinlets. The con- tact of the Talara sandstones with the Salina is in all places sharp and distinct while at some places where the Salina is missing, the Talara lies directly upon the older rocks.
The Saman sandstones outcrop in their typical Chira Valley facies at the west side of the City of Paita. They are yellowish, concretionary sandstones and are very fossiliferous. They lie directly upon the basement schists thereby proving the in- dependent transgressive character of the late upper Eocene sea. It was from these Eocene exposures at Paita that the earliest Tertiary fossil to be described from South America by D’Orbigny had been obtained. Later, other collections were made by Rai- mondi and Orton which were described by Gabb, These out- crops of Saman sandstone are separated from the Chira shale exposures to the east of the city by a major fault.
The Sechura Miocene was previously known in outcrop only along the east side of the Illescas Mountains but a small area of Miocene exposures has since been found at Cerro Chocan near the northeast end of the Cerros de Aspereria [Olsson(6)]. Gerth showed Cretaceous outcrops at or near this locality on his small sketch map which may or may not refer to these Miocene beds. The exposures are limited in extent and consist mostly of a
169 CRETACEOUS OF PaITA: OLSSON TL
yellowish shell limestone and concretionary shale which rests with a basal conglomerate upon a crystalline floor. The fossils, mostly molluscan, are badly wind eroded but amongst others, have the following forms: Dosinia illesca Olsson, Cardita, sp. Corbula cf. acutirostra zorritensis Olsson, Semele, sp., Conus bravo Spieker, Conus multiliratus Spieker, Turritella, sp., Antillophos sp.,lhanetia (Solenosteira) sechurana Olsson.
East and southeast of the city of Paita are the small peaks of the Paita Mountains. They form two groups of mountains, the western set known as the Silla de Paita and the eastern set as the Cerros de Aspereria. The Silla de Paita is the higher and more rugged, its principal peaks in the northern part having an elevation of about 380 meters. The Cerros de Aspereria are much lower and in many places are completely smothered by dune sands. The trend of the Silla de Paita is northwesterly but a large part of its marginal area has been lowered or planed off by the tablazo sea. The Cerros de Aspereria have a north- easterly trend and are therefore parallel to the normal, structural erain of the Amotape Range some miles north of the Chira Valley. At the south, the Silla de Paita and the Cerros de Aspereria are weakly joined by a low pass or wind gap about six or seven kilometers north of the coast. Although these two mountain groups are similar in their rock formations, they are evidently parts of two major fault blocks, the fault separating them passing from the coast at La Casita “the end of the Creta- ceous breccia sequence” northward along the east side of the Silla de Paita Mountains to the tablazo break and change in geol- ogy at the City of Paita. A fault with a similar trend borders the east side of the Illescas Mountains and separates the old mountain rocks on the west from the Tertiaries of the Sechura desert on the east. In both cases, upfaulting has occurred on the west side.
The Cretaceous outcrops at La Mesa along the south side of the Cerros de Aspereria are believed to be older than the beds at Tortuga. The La Mesa beds are relatively fine-grained rocks, in part limestones and represent deposits formed by a transgressive sea across a relatively flat, peneplained floor. The Cretaceous in the coast section at Tortuga is coarsely clastic and contains only
12 BULLETIN 111 170
an occasional interbedded marine or fossiliferous layer. A marked change in the source of sedimentation has therefore oc- curred since the formation of the basal beds at La Mesa. The base of the Tortuga breccias has not been seen but they prob- ably overlap to some extent upon the old rocks forming the core of the old Paita Mountains. The formation of these thick de- posits of shingle beach accumulations can only be explained as the result of a lively erosion in nearby mountains in process of uplift. This period of orogeny, correlated with the change in character of the Cretaceous sediments, is probably connected with the formation of the Paita and Illescas fault system (prob- ably also the Pananga fault of the Amotapes) which is therefore of Maestrichtian age although movements have occurred along these faults at intervals during the Tertiary. The Cretaceous sections at La Mesa and Tortuga therefore offer an excellent ex- ample of the close governing influence of tectonics(7, 8) in the petrographic character and mode of formation of a sedimentary deposit.
THE PAITA CRETACEOUS
The most complete section of Upper Senonian rocks yet known in northern Peru is found along the south coast of the Paita Pen- insula from near Foca Island eastward through Tortuga to La Casita and in smaller patches at La Mesa near the south corner of the Paita Mountains. These outcrops were first found by the geol- ogists of the Dutch Shell (the Bataafschen Petroleum Maats- chappij) in 1925 and a small collection of fossils from these beds was briefly described by Gerth(2) in 1928. Gerth indicated sev- eral outcrop areas along the south side of the Cerros de Aspereria but only that at La Mesa itself has been seen by us. The locality at the northeast end of the Cerros de Aspereria or near Cerro Chocan is Miocene. It is quite possible that Cretaceous beds are exposed at points along the east side of these mountains but outcrops must be rare as the area is covered with deep and con- stantly shifting desert sands. The Cretaceous at La Mesa and in the sea cliffs at Tortuga are the shore-facies of more marine beds belicved to underlie Sechura Bay.
171 CRETACEOUS OF PAITA: OLSSON 13
\Vhat we believe to represent the lowest and oldest part of the l‘aita Cretaceous are the rocks exposed at La Mesa which is a small, flat-topped hill at the south end of the Cerros de Aspereria. Only at this place do we actually see the base of the Cretaceous series which lies with marked unconformity upon the much older, metamorphic and crystalline rocks of the Paita Mountains. These exposures consist principally of a yellowish sandstone and sandy shale, sometimes concretionary and generally fossiliferous. The sharply keeled ammonites (dAustrosphenodiscus and Pac- iceras) are common here, together with small gasteropods and bivalves, but the fauna as a whole is not well preserved because of severe wind-erosion. Gerth called these beds the Sphenodiscus- Schichten. The ammonite beds are overlain by a massive lime- stone formed mostly of rudistid remains but a few other fossils such as Acteonella are common in the lower layers. This hori- zon is Gerth’s Act@onellen-Rudistenkalkstein and from it he de- scribed Pironea peruviana. Although the limestone is highly fos- siliferous, good specimens are very difficult to extract in fit con- dition for identification. Besides Actzonellas, our collection con- tains only a few fragments of a radiolite showing the forked vascular markings of a Sauvagesia.
The Cretaceous exposures at La Mesa and those in the coast section at Tortuga are separated by a wide area of flat tablazo without any rock outcrop so that the stratigraphic relations of the two sections cannot be observed, In contrast to the relative- ly fine-grained and typically marine beds at La Mesa, the rocks at Tortuga are composed mostly of coarse, breccia-conglomerates and contain fossils only in a few, and relatively thin horizons.
The coast between Foca Island at the west end of the penin- sula and La Casita to the east, is bordered for most part by a tablazo escarpment about 65 meters in elevation, This tablazo plain extends inland to the foot of the Paita Mountains around which it overlaps in shore-line form. Along the coast, this tab- lazo overlies segments of Tertiary and Cretaceous formations which in the shore cliffs is distributed roughly as follows: at Foca Island and for a distance of about two miles east, the principal exposures are the Amotape slates; they are followed by a small
14 BULLETIN 111 72
segment of Cretaceous sandstones with rudistid remains. The coastal zone immediately south of this block is formed by Tertiary shales which extend for a distance of about a mile and a half. No fossils are known from these Tertiary beds but in appearance the beds resemble the Chira. The base of the Tertiary is formed by beds of conglomerate and breccia which lie on Cretaceous sand- stones. The main Cretaceous section begins at this point, about two miles north of the fishing village of Tortuga and continues without major interruption to La Casita which is merely a small indentation in t-< t Ll.z_ escarpment. The Cretaceous in this sec- tion is formed mostly of a slate breccia-conglomerate and more rarely sandstones. It is usually poorly consolidated, well bedded and dips fairly regularly northward at angles varying from 17 to 30 degrees. The uppermost part of this section is formed by the Radiolite sandstones which is exposed opposite the small guano rock known locally as “La Mina de Perico’’. It is a bluish- to ereenish-colored rock when fresh, rather massive, its bedding indi- cated mainly by lines of small concretions. The bedding is more regular towards the base and seams of conglomerate begin to ap- pear as well as lavers of fossils Remains of Sauvagesia peruviana are common in the upper and main parts of the sandstones but most specimens are badly broken. Some of these fragments are from individuals of large size. A few bones, fossil wood and frag- ments of shells were observed.
Fossil layers begin to appear in the lower part of the Radiolite sandstones and form a transitional zone between the sandstones proper and the underlying breccias. In the paleontological part of this paper, these fossil beds will be referred to as the Baculites zone or the Upper Breccias. Fossils are very abundant here, most of the species are large, thick-shelled and many in excellent state of preservation. It is a typical Monte Grande faunal as- semblage, most of the species known from Monte Grande occur- ring here. Prominent species in these beds are Pseudocucullea gregoryi, Trigonarca meridionalis, Trigonia gerthi and hopkinsi, Roudaireia peruviana, Cardium briiggeni and amotapensis, Pe- rustrombus wheelert, Torgnellus peruvianus and many others. Ammonites are rare except Baculites lyelli which grows to a large
1/3 CRETACEOUS OF PAITA: OLSSON 15
size. The thickness of the Radiolite sandstone, including the fossiliferous beds below it, is estimated as about 500 feet but care- ful measurements have not been made.
Under the Radiolite sandstones there is a very thick sequence of slate breccia-conglomerates, usually so coarse that when seen in small patches might be mistaken for basement rock in outcrop. The color is usually a limonite red but green and gray beds as well as layers of a pure white sandstone are interbedded. Near the middle of this sequence at the small fishing village of Tortuga, the breccias contain a few, relatively thin layers of fossiliferous, pebbly conglomerates and shaly sandstones. About three of these fossiliferous bands were found which for sake of convenience were called the lower, middle and upper fossil beds of Tortuga. The fauna is essentially the same in all layers. Beyond Tortuga, the breccia-conglomerates outcrop continually along the shore and at many places form high, impassable cliffs.
The Cretaceous at Tortuga and La Mesa is roughly divided as follows:
A. The Radiolite sandstones with the Baculites zone at base. Thickness about 500 feet.
B. Breccia-conglomerates with interbedded sandstones. Thick- ness not known but probably about 1000 feet.
C. The Tortuga fossil beds. A zone of thin fossil beds within the breccias and probably together about 200 feet in thickness.
I). Lower Breccias, unfossiliferous, thickness unknown.
E. Interval without outcrop, unconformity possible.
*. Acte@onella limestones.
G. Austrosphenodiscus-Paciceras shales and sandstones.
H. Basement of complexly folded crystalline and metamorphic rocks,
16
BULLETIN 111 : 174
FOSSILS FROM THE MONTE GRANDE AND PAITA UPPER SENONIAN
INiiCulamaess piensa eee ee ee eee So tee Tor. Pseudoencullsa eregarya Olsson (2:25) ee MG. Bac. Psendocucullsear (parvanay. mm: “spy ees eee LMs Peruarea, pectunculoides) i. isp. ee ee ae Bae.
Ineanopsis acariformis, n. sp. Tor.
Srewiarca, TPeruviana. ens Asp til sbeRel! Sisley ee eee eee LMs. Mytilus jsiematus OlSsOn pe 5-. = ne oe es ee ee ee Tor. MG. Volselilawicenval mi. (Sp ctr ey kr ete Re ee ee ie ere Tor. Violsellayportana! Olsson sess. 8 ste eis BONE poe eee eee ee MG Pedalion woodsi Olsson Tors biGe
Gervillia incertans, n. sp. Inoceramus, sp. A. Inoceramus, sp. B. ARTO TINT ANAS Sst ct eek ste aes re ie el aor on a. Meee Spe ea tne: eee Ostrearapallip ave: (Spot soe ek Ae ae ea ee aie eee ee hee Ostresien (Uo phiay)eisechiumcct pits nS]: pees eats oe ee mene n eee seen Ostrea (Lopha) stappenbecki Olsson O3strea, sp. Pam nase iS poses) wsencer et SEI e MRP EN Ee rte RMN en UNE EEN ie Be ever one ‘\rigonia (Seabrotrigonia) gerthi, n. sp. Trigonia hopkinsi, n. sp. Na LAIMNVA: OSPR (ei eee wie oe AUER RS ae) ED ee a eRe Peripl ema merm ray eis {Spe sere: seer ee ee eg ee Pholadomya koughti Olsson Spondylus hopkinsi Olsson IP iivoeUley lovewpientsulewaeal: OVO, oe ce eee eee eee needa
Roudaimelasperuvaanay Olsson ss ee oes eee eee rs . LMs Roudaireia auressensis Coquand
- OMe
Glossoeardia (Tortucardia) stephensoni, n. sp. LMs. Corlbiculale mer Ci Omens h prilyss yee te eeeees eee eee ee WVenericardia ‘weberbauer! Olsson) = ee Orbienyapaciica "O'SsOn), see en eee eee eee SENURENEXESIIE), TOLeTRU AMO 1a YO)5 Soe ataee ee tere ee eee MG Pironsa, mperuviana Gerth 92 ee ee Acteonella Is: OPA URUD AN YONG TEMES, Vl SYD eae ecco ce cee eeeeetneceeenine feceieneetcneton neces Bae. Cardium ((Rerucardia) ‘bruggeni, my isp. 22. MGs {Baca anise Car dimmer otap emi st. ©llssomyesseel meee nies Bac. MG. Cardium (Gineacardium) “mellisum;, u5-sp.) 2 eee Tor. LMs. APhrodiMaspaciica, TM. Spx, oe 0+ wl ee eae ee Bae. Aphroding «ch -auca dvOrbigny 05. oee ek eee eS Bae. ApuTOdinaSpecClOsa,- Ns Sp. oe. nats) eee Ree es Tor Apkrodima, (Sechurina) australis, m- sp. 95 5 Ves Bae. IhegumenyPeruvaanum, “WGP. eo spe See ene: Tor TIGA), TORUCTTC RY, I, IED cen seco eos ee Tor.
IM RTUD TING HNCKENSS, OUNCES TG TOG ageecceeceeernsee eee Bae. Mulinoides chicama, n. sp. ............. Sa ie DEA Oe OAR We Tor Macrodonax) speruvianas 1. aiSps ys). ee ee Bae.
Tellidora (Tellipiura) peruana, n. sp.
7
5 CRETACEOUS OF Parra: OLSSON
DI ScaU nies S10 pm gp eee eS ok a ee cette San MG. Ismenmiay bomara, OMSON, cece ose! eeee sane eee: OR Fe eee MG Panopetrailiay nm. sps .2.--.5..-60--2---2--- pa Pee en ee er ae Bae. Cates UTES @ Uns rs Ets) 0 ey gn MNO SRS Ese ene eee cee ere ee Tor. Corbula montegrandensis Olsson ..............-..----------+21ee-2-eeeeer te Bae. Gorka, DrOppi Mee Spe ke. ee See eae eee eee seg Bae. Mec tusEaGS@hid ts etly MSP Spaces. ee oe. ee eek ee eee stan Bae. BR 11 SRV RSP) oreo eta Sg et te eee nc aewe Tor. Pseudomelamial simplex, mi. Spe 2-2 22sec ee nwa tne Lor: ING rubaen ay aicany mySP eee = ter eee Seca eee teens Tor. Mesmaiera, speruviana, (Olsson. 220) es eae ano eee eee MG. Stal mae nia, v1. (SPe ce. so ec a cette BE Ao to ee Tor. MVC Seiad py ANd J A TPS a Sac wee ee ee eee ee Scam Tor. Mesalia, speruviana. Olssont 22222. 5. a2: a0. a coe ecg ee eee MG. eosin, itera er OlSSOT enc, 28 me ee caer nee we eee MG. Wino dise lvey srebeanlely © Blo Spo) eee es Sees teeter eee aera ees ae Tor. Woodsalia paitana robusta, m. subsp... --_.-2---2---cseee--------o-- Tor. ameritell acer ay elle Se xc. meee ere: nae eee fe eaten een mec eeees Bae. Murritellay qprechiray. N- Spra) Sec. hn2 steeds oe eee LMs. poten Gel ce Seu OSA gall. Spe, pee ee. <_ eee eee eee ee Tor. Mearrast heel AINA) Wiese ens ea sc 2 ee eee cae ce esta ee Tor. Pirritelia esol satan, Hsp ye cece eee (s Neen eee te ee coe ce Bae Miner te Mayomity a. TS Sp. cele cea. Re ees 22s eo ere Tor Threat lay pEel Los OWI) ys Se ee en, ose ee cen cactee eee aon ec Bae Ditayrars tts ee by eUTsts Sa YO oe ee en Pan de Azucar Sew haamaritsesl enen tier ee bo Tee G10 @ trea et 0 eee mE Bae Sechumitella- chacapoyale Ne SPs ox... 4 octececces ce ede e ea itcewn ee sweet Bae Seu donne] axa see te Sree meets meee csc oe eed eae eR ee nae Tor. IMI@lienmeniesley TEC TOG MS NS cece poe ee ee eee eee ese ee Tor. GlancontamcOrdalis, sis (Spi) es Oko een Ae eh es Bae. INCLU TONE, THOCIOSUE Ty SOs sia ee eee shee theta eetseosnecteeseee se cuoseaneecer Tor. Woditanunus;costabusy Ts “Speco. 2... Se ee) ed Tor
iSlorioclava ance, -S)s) x. eeyse: iow pe ee. to OES
ay
LMs.
revaCaLyan qOehUvianlary te Wisp.) ce see see ce we ene ee eeel Tor Mrocotanlaxeelesang. mie sp.0 Se eae eee es Tor MMnAHASHA “COCOMIA.. Ty .ODs, oo. os. Gke cw ase eh eA soe ke Tor IBvrazus; PeLUVIANUS, “De SP: 20. 0.e4 el ee tee ees. Tor. SMOG A MeN! ESA sUNS| TN YD ye teen eect ke aoe eee Toi Sy pAnotomus, OIUTICALUS, \H, SP ogy os.c.k cere ee oes eee Tor. Rhinotamides: Ludis, me sp. se = omen Ba dee Tor. Calypireay apertaSolander 1.5 22.0 ee a Bae. MG. Tor slg euy ouoT is es Soe oY ete OF EP SNES) pet ae LE aI a BE een a pede ee Bae. PAGMTNEGTE LORG OA wits Sy ee ne ees See ek eee Tor Atmipullliniase cum arash Sp) enteees= wake pene wee ies es eee ae Tor. AriChUn ae pAChiCayg ly Sig ee kets, Bel! date ge see by aN tents tt Bae. Calyptraphorus -hopkins: Olsson’ -2\_ 2 .22..22.<:...24 cai MG. Bae. ANomeaneMINTS, FOOMUNAANAS, Tak D5 eect cst tee re MG. Bac. Perustrombus wheeleri, n. sp. ................ OL eRe a A anny 2 ee Bae. Oxthostrombus tonbuUsensis sms ass pce enero ee eee eee Tor. Orthostrombusmcypretormis Olsson pes see ee eee MG. Se tid OL Va eats peter eee Mee a Bk ch RL Pe Nene: MG.
Fasciolaria ef. bleicheri Thomas and Peron MG.
18 BULLETIN 111 176
[NEISNOMGNENE), SSCOIMBTE, I, SY ceceereneesgoeenetee ee oncncecenoeceetece BNP ee a Bae. radians. tao alls. Wily ASI) so oad saesssneet a eee errs eae eee ee ere eee Bae. Rhomibopsissmeridiomallis, yan) Spe sete eee eee eee Tor. HUSinnIsCOnRDISH wp.) oe de ee en eS eee Bae. Lissapiopsis' ? calappa Olssom __.-...2.-.2022-.- Sera, pes E MG. 4 Matron RES OA oe a eee UE NN Cee eee Serre et Ee a ee) Bae. Violtibae dN Cal ast S sae sore sonar eee enue Oe My. WR ws et, Bae. AWVONIEO GOT OS eee Tal CLI Onn ea S eye 7) ote Bae. tryna (COMCHAL,| AURIS Pn: 90s, Jace et hee aes ee ea eee ee Tor. Baculites yelled? Orbiom yo fee eee ne Bae. Mnmmilates| qoenuiviamus em) (Sp). ps8 ce cee ewe eee Bac. MG. Barapachy@iselsy, Spas. 2g <hr ee ee ee eee Bae Coahuilites (Austrosphenodiscus ) peruvianus: Gerth LMs. Pacicerasm pac Guay Ma. SS y see -.cs ease eee weet ee eee LMs. Paciceras-<certhit) ms Spe ie es she ore 2 eee ere eee LMs. Salle O ShRACO US tk ute Pe eke et eetaee ee | yee alee oat ere Tor Seal poe Moanin aS) we ne eee ee eee Tor @alllvamassay Spy... ees eit eee eS ee eee eee or: Montastrea. parimasensts) (Welsh... sce ee ete ree eee Bac. MG.
The locality abbreviations refer to the following:
MG. Monte Grande near Negritos.
Bae. Baculites zone.
Tor. The Tortuga fossil zones.
LMs. La Mesa.
Pan de Azuear. Pan de Azucar near La Brea.
In the Negritos oil-field, a subsurface formation has been en- countered in some deep wells containing a very late Cretaceous or post-Navarran microfauna. To these beds, the name Mal Paso was proposed by Wiedey and Frizzell in 1940 and more recently, the fauna, composed entirely of small Foraminifera, has been de- scribed by Frizzell(9). The Mal-Paso is not known in outcrop but in well-borings consists predominantly of shales which underlie with apparent conformity the main oil sand in the older part of the Negritos field and which may therefore mark the base of the Eocene Negritos shales. The formation has a thickness of about 7000 feet, below which lies a zone of conglomerate which ii turn rests uncomformably upon beds believed to belong to the Middle Cretaceous Copa Sombrero,
The Paita Cretaceous, because of its sandy and clastic charac- ter, has not yielded any microfossils aside from ostracods and small plates of a Scalpellum so that a paleontological comparison with the Mal Paso is at present not possible. As pointed out by Frizzell, the Mal Paso Foraminifera which comes mainly from the upper 3000 feet of the formation, are younger than the Navar- ro and hence must be younger than the Monte Grande and the
ei CRETACEOUS OF PaITA: OLSSON 19
Clavulina shales. Such common Foraminifera as Spiroplecta- mina greybowskii Vrizzell and Marssonella oxycona Reuss cer- tainly suggests a correlation with the Tamesi (Velasco) of Mex- ico and the Lizards Spring fauna of Trinidad, and referred by most authorities to the Danian. Whether the lower Mal Paso shales and the underlying conglomerate are the age equivalent of the Monte Grande and Clavulina shales cannot be decided at present without fossils. If these deep beds should eventually yield fossils of Maestrichtian or Navarro age, a correlation with the Monte Grande sequence would be indicated.
At Monte Grande and at Paita, the Tertiary formations which overlie the Cretaceous sediments belong either to the middle Eocene or still higher horizons and are strongly unconformable. It can be pointed out again that the Negritos field with its un- usually thick and very complete Eocene section, is the very cen- ter of the Eocene sedimentary basin in northern Peru with the oldest Eocene occupying a very small area. If transitional Cretaceous and Eocene beds are found anywhere in South Amer- ica we should expect them here.
The Turritella bartsia described in this paper comes from a ser- ies of coarse, shore-facies sandstones outcropping in the south bank of Quebrada Ancha near Pan de Azucar west of La Brea. These beds rest unconformably upon the Pananga limestones. Their age is not definitely known as no other fossils have been found in them. They may belong to the Monte Grande or to a
lower Eocene horizon. AGE OF THE PAITA CRETACEOUS
A late Cretaceous or Upper Senonian age for the Paita se- quence is clearly indicated by its fauna. The presence of a large Baculites belonging to the anceps-vagina eroup. a typical Upper Senonian Parapachydiscus, large, rcb st ‘-r s £ Trigonarca, Roudaireia, Pseudocucullea, members of the Inoceramus cf. bal- ticus group; and rudistids closely allied to Upper Cretaceous species elsewhere is definite evidence of its late Cretaceous character, These fossils would seem to indicate a Maestrichtian age for the entire sequence but because of its great thickness and well-differentiated faunal zones, it is equally possible that the section may also include horizons somewhat older than the Mae- strichtian.
20 BULLETIN 111 178
In the Andes, the most widespread of the marine Cretaceous deposits are beds which extend from the Turonian into the Lower Senonian possibly as high as the Santonian. These formations contain a rich fauna with several ammonite zones in which spec- ies of Coilopoceras, Barroisiceras, Tissotia, Heterotissotia, Peron- iceras, etc., are a few of the dominant and characteristic forms. These faunal elements are entirely absent from the Paita Creta- ceous and show that no part of the section is as old as the Lower Senonian,
Gerth, without information as to the field sequence of beds, considered the ammonite locality at La Mesa or his Sphenodiscus Schichten as belonging to the Maestrichtian. This age assign- ment was based largely on his identification of these sharply keeled and more or less noded ammonites as a_ subspecies (peruviana) of the common Navarran Sphenodiscus pleurisepta Conrad. The beds at La Mesa belong to the lowest and hence the oldest part of the Paita Cretaceous and lie directly upon base- ment. The sharply keeled ammonites so abundant in this lower horizon belong to two genera and three species none of which are closely related to the Texan Sphenodiscus pleurisepta. They are associated with a relatively small Roudaireia, medium-sized Pseu- docucullea, small Trigonias, etc., a faunal assemblage which is very similar to that found in the basal Umir and the Mita Juan in Colombia and Venezuela. The rudistid, Pironea peruviana Gerth, comes from the slightly higher horizon of the Act@onella limestone. The Act@onella was referred by Gerth to Act@onella (Volvulina) cf. levis @Orbigny but the material I have seen consists only of cross sections and cannot be closely determined.
The fossil zones at Tortuga village or in the middle Breccias contain a fauna which is largely confined to it and consequently does not yield much evidence as to its age. On a casual inspec- tion and disregarding its obvious stratigraphic position below un- questionable Cretaceous, this fauna might easily be mistaken for lowermost Eocene. Some of the cerithids and potamids, includ- ing Melanatria, the Mesalia janja, some of the Turritellas and the presence of true Calyptrea, might all be considered as Eocene forms. The cerithids and potamids belong for the most part to
179 CRETACEOUS OF PaITA: OLSSON 21
new genera and have no similar species in the Eocene so far as known. Mesalia janja, although somewhat similar to some Eo- cene species like fasciata Lamarck, is perfectly distinct and what is more important, the same species occurs at La Mesa associated with ammonites. The Calyptr@a seems identical with aperta Solander, a common Eocene species in Europe and America, but it occurs both at Monte Grande and in the Upper Breccias or Baculites zone in company with ammonites, etc., so that its oc- currence at Tortuga has no age significance. On the other hand, there are a few purely Cretaceous genera such as Legumen and Anatimya as well as several species which range upward to the Baculites zone or downward into the La Mesa. Of these we may mention, Mytilus signatus, Pedalion woodsi, Cardium mel- lisum, Perustrombus and Mesalia janja.
The fauna from the Baculites or Upper Breccia zone is most certainly Maestrichtian. It is essentially similar to that of Monte Grande. The Sauvagesia peruviana which occurs in the upper- most sandstone is very similar to “Durania’” curasavica (Martin) from Curacao and Cuba. Most of the bivalves and gasteropods are characterized by large and solid shells or the highest stage of their evolution. This is certainly true for such species as Roudaireia peruviana, Trigonarca meridionalis, Pseudocucullea gregoryi, Trigonia hopkinsi and the © striking Perustrombus wheelert and Torgnellus peruvianus. The ammonites are poorly represented in these upper beds but include two very important forms, the Baculites lyelli VOrbigny and a Parapachydiscus allied to the Parapachydiscus dossantosi Maury from eastern Brazil.
In resumé, it seems probable that the Austrosphenodiscus-Pa- ciceras beds at La Mesa are of Campanian age. The Tortuga breccias, including the Baculites and Radiolites sandstones, are Maestrichtian.
22 BULLETIN 111 180
RELATED MARINESFOULIVALENT S:Ob Gir PERUVIAN UPPER SENONIAN IN SOUTH AMERICA AND WEST INDIAN REGION
CHILE
Fossiliferous late Cretaceous rocks have been known for many years to occur on the Island of Quiriquina in the Bay of Concep- cion on the coast of Chile. The first fossils were described from here by D’Orbigny(10) in 1842 and although including a Trigonta (the widespread Trigonia hanetiana) were nevertheless consid- ered as Tertiary. The age of the Quiriquina section was definitely established a few years later by Darwin(3) on the discovery of specimens of a baculite. Somewhat earlier Lieutenant Belcher (11) had found an ammonite near Tomé, so large that only a fragment could be removed. Darwin’s fossils were described by Forbes(12) who correlated the fauna directly with the Pondicherry of India. A large number of Cretaceous fossils, many from Quiriquina and Tomé, were described by Philippi(13) but most of these so-called species are indeterminable, being based on casts and unrecog- nizable fragments. In 1895 Steinmann gave the name Quiriquina formation or Quiriquina-Schichten to the Cretaceous beds in this region and worked out the detailed geology and succession for the first time. The results of Steinmann’s(14) work and fossil collecting is recorded in a series of papers in which Moricke and Deecke are co-authors. The Cretaceous at Quiriquina lies with a relatively flat dip upon a complexly folded, crystalline basement and is overlain by coarse Tertiary sandstones and conglomerates, a stratigraphic set-up similar to that seen at Paita and at Monte Grande, The most recent study of the Quiriquina fauna is by Wetzel(15) but which adds little of note to the earlier work of Stemmmann and Wilckens(16). The fauna is relatively varied, es- pecially in ammonites and besides other mollusks contains re- mains of plesiosaurian reptiles and one species of bird. Of mol- lusks alone, about 85 species are known,
181 CRETACEOUS OF PAITA: OLSSON Ze
Most students of the Quiriquina fauna, as well as Kossmat(17) and Uhlig, have called particular attention to the marked affini- ties of the Chilian ammonites to those from the Ariyalur and Pondicherry of India as well as with the Nanaimo beds on the Island of Vancouver and other localities in Puget Sound. The affinity of the Chilian Quiriquina fauna with the New Zealand Cretaceous(18) is even more marked and includes not only simi- lar species of ammonites but extends to the other mollusks as well, the most striking forms being the Trigonia hanetiana, Lahillia, Thyasira and some allied types of gasteropods. To the south- ward, the Quiriquina fauna, through its ammonites, ties in with the beautiful assemblages described by Kilian and Reboul(19) from Seymour Island and Snow Hill in the Antarctic.
With northern Peru, the affinities of the Chilian Cretaceous is not nearly so close as we would have expected from the foregoing account of the widely distributed character of the Indo-Pacific ammonite fauna. This condition has been explained as due to a land barrier separating the two areas of deposition, but it is worthy of note that a similar distinction in faunal makeup be- tween the Chilian and Peruvian provinces was true for the whole Tertiary. The north Peruvian Cretaceous is decidely more trop- ical in character, as indicated, for instance, by the occurrence of rudistids, lacking in Chile and in New Zealand. The absence of Trigomia hanetiana, Lahillia and other characteristic Patagonian and Chilian types from north Peru is probably also due to climatic or zonal control. Only Baculites lyelli and more ques- tionably the Aphrodina cf. auca are common to the two regions. If the ammonites were more abundantly represented in the Peru- vian deposits, much closer ties would probably be shown.
The Quiriquina beds have been referred to the Upper Senon- ian or Maestrichtian, Stephenson(20) has noted the similarity of Parapachydiscus quiriquine Philippi to arkansasus of the Nac- atoch sand member of the Navarro as well as the presence in the fauna of Discoscaphites constrictus (Sowerby) which confirms their correlation with the European Maestrichtian.
94 BULLETIN 111 182
COLOMBIA AND VENEZUELA No Upper Senonian rocks are yet known in Ecuador. In Co-
lombia, some excellent Maestrichtian or at least Upper Senonian faunal assemblages have recently been collected from various lo- calities but the fossils have not been described. The Colombian Maestrichtian shows close affinities with the Peruvian, the most remarkable of these are from localities in the upper Magdalena Valley. These beds have a rich fauna in which large, thick- shelled species of Spondylus, Roudaireia, Pinna, Cardium, Pseu- docucullea, etc., closely allied to Monte Grande forms, are the dominating elements, The relation of the fauna from these beds to the Roudaireia-Pseudocucullea-S phenodiscus Parahyba_ hor- izons of eastern Brazil seems equally as close; one of the most in- teresting ties being a large crab allied to Nanthopsis brasiliana Maury.
The lower Umir and the Rio de Oro formations have yielded small faunules containing Coahwilites, Inoceramus, Pseudocucul- lea, Cardium briiggeni, Breviarca, etc. As a rule, the fossils are not well preserved but would seem to indicate a possible corre- lation with the Austrosphenodiscus-Paciceras horizon of the Paita Cretaceous and may therefore be as low as the Upper Campanian. That these fossiliferous beds do not represent the topmost part of the Colombian Cretaceous, as is so often expressed, is quite evident.
The Mita Juan of western Venezuela is the correlative of the Umir. Its lowermost beds have yielded a meager molluscan fauna containing Roudaireia and sphenodiscid ammonites but the fossils are poorly preserved and critical comparison cannot be made at this time. They would seem, however, to belong to about the same level as the ammonite horizon of the Rio de Oro and the lower Umir. Roudaireia and fragments of very large Pseudocu- cullea have been found at a few places in east central Venezuela. At many of these occurrences, the Cretaceous fossils are from boulders in Eocene conglomerates which serve to show that a definite erosional interval occurred before the deposition of the Eocene sediments,
183 CRETACEOUS OF PAITA: OLSSON 25
A few Maestrichtian fossils, including Roudaireia have been re- corded by Waring and Harris(21) from Trinidad. To this record, Rutsch(22) has more recently addled Hamulus and Sphenodiscus. These fossils are derived from blocks or boulders from Eocene clastics or from the Mount Moriah boulder beds of upper Eocene age.
BRAZIL
A small but very interesting Upper Cretaceous fauna has been described by Maury(32) from the State of Parahyba do Norte in eastern Brazil. These fossils come mostly from a limestone quarry on the Rio Gramame, near the city of Parahyba. Two faunal zones are present but which are probably merely facies variants and do not differ importantly in age. The first zone is characterized by a rich ammonite fauna in which are numerous species of Parapachydiscus, Pseudophyllites and Sphenodiscus. Some of the Parapachydiscus, notably dossantosit seem very sim- ilar to the single fragmentary Parapachydiscus known from Paita. The second zone has a pelecypod fauna in which are large, thick-shelled species of Roudaireia, Trigonarca, Pinna, Pseudo- cucullea (Eusebia), Venericardia, Pholadomya, etc. Many of these species, because of their solid, heavy shells adapted to a coastal environment, show relationship with the Monte Grande facies of northern Peru.
BONAIRE AND CURACAO
Upper Cretaceous rocks occur on the Dutch Island of Curacao as well as Bonaire off the coast of Venezuela, but aside from a few rudists from Curacao, the fauna has not been re- corded. The Cretaceous formations of the islands are said to be dominantly volcanic in origin with diabases, porphyrites and tuffs in which are intercalated beds of chert and limestone. Two ru- distids are described by MacGillavry(24) from the Seroe Teintje limestone on Curacao, the most interesting of which is Durania curasavica (Martin), a sauvagesinid radiolite. This species be- longs to the same, low, spreading type as our Sauvagesia peru- viana, from the uppermost Cretaceous sandstone at Paita, and doubtless the two forms should be referred to the same genus.
26 BuLuETIN 111 184
The Curacao species has also been identified by MacGillavry (26) trom the Loma Yucatan limestone, north of Camaguey City in the east central part of Cuba. MacGillavry favored an Upper Cam- panian age for the Loma Yucatan limestone and a Maestrichtian age for the Havana formation, s. sfr., or Barrettia beds. | Some corals (Pijpers, 1933) and Act@onella have also been reported from the Dutch Islands which suggest a faunal assemblage sim- ‘iar to that known from beds immediately beneath the Eocene limestones of San Juan de los Morros in Venezuela.
JAMAICA
In Jamaica, an interesting Upper Senonian section has become known mostly from the field and paleontological studies of Trechmann(26). The rudistids and caprinids predominate in the fauna, many of the species are closely related to forms from Cuba, and some reach gigantic size. According to Trechmann all the Cretaceous or Rudistid limestones in Jamaica belong to one and the same high and vertically restricted horizon. This limestone overlies shales containing a fauna having a Campanian aspect. Shales are also found overlying the Rudistid limestones at a few places but have yielded only a small fauna. The rudistids contain amongst the Hippurites, such genera as Orbignya, Barrettia and Prebarrettia while the Radiolites have reached the stage of their evolution in which the ligamental flexure has become lost. This stage, according to Douville, was reached amongst European species of the Radiolitidze in the Dordonian (Maestrichtian) and during the Turonian for most species of the Biradiolitide.
The Cretaceous shales which underlie the Rudistid limestone have yielded a fauna comprising about 55 named forms, includ- ing five ammonites. This fauna like that of the Jamaican Eocene is decidedly European, north African and even Indian in affini- ties, a feature repeatedly emphasized by Trechmann. This char- acteristic 1s equally true for the Peruvian Eocene and Cretaceous as well. The Providence shales fauna shows some resemblance to the Peruvian Cretaceous. Thus Roudaireia jamaicensis is so nearly related to Roudaireia peruviana that from figures alone it is difficult to decide whether they should be separated. This group
lees oe « , > '" ete 2 = of igh, sharply keeled forms, differing mainly from the more
185 CRETACEOUS OF PaArITA: OLSSON 27
typical African Roudaireia auressensis by its smoother sculpture, is a widespread type, being found, outside of Jamaica, in Colombia, as well as in Peru. Roudaireia peruviana commences in the basal Upper Senonian at La Mesa where it is comparatively small. It is not known from the middle zone at Tortuga, perhaps because of unfavorable environment but reappears in abundance and in large size in the Upper Breccia zone.
There has been some interesting discussions as to the age of the Jamaican Cretaceous sequence. Trechmann from his study of the mollusks considered the Rudistid limestones with Barrettia as Maestrichtian and the underlying Providence shales as Cam- panian with the possibility of the lowest beds as Middle Senonian. On the other hand, Hawkins(27) who studied the echinoids col- lected by Trechmann in the Rudistid limestone considered their age as low as the Cenomanian or Turonian, Douville(28) notes, however, that according to Lambert, some analogous forms of echinoids have been recorded from the Campanian of Persia. Trechmann’s opinion as to the late Cretaceous age of the Jamaican beds received much support from Spath’s(29) studies of the am- monites, comprising five species, collected from the lower part of the Providence shales, a considerable distance below the Rudistid limestone, This ammonite assemblage which contained amongst others, a Parapachydiscus allied to the European gollevillensis, Spath considered as Upper Senonian, not older than the Campan- ian and probably still younger. Most later writers who have had occasion to consider the Jamaican Cretaceous have followed Trechmann in his age assignment.
OTHER AREAS
Porto Rico, Haiti and Cuba, each have important develop- ments of Upper Cretaceous beds but only in Cuba do these for- mations contain good fossils. The Cuban Cretaceous fauna is, how- ever, mainly rudistid which has been described in part by Palmer, Douville, MacGillavry, Rutten and Vermunt.- The Havana for- mation contains Barrettia amongst other rudistids and is there- fore equivalent to the Rudistid limestone of Jamaica. Palmer and others consider its age as Maestrichtian. This formation in many places hes directly upon basement. As noted by Trech-
28 BuLuETIN 111 186
mann, beds corresponding to the Providence shales seem to be missing in Cuba. With the rich Navarro and Ripley faunas so beautifully monographed by Stephenson and Wade, there seems to be very little in common with Peru. The same is also true for the Mexican Cretaceous. RESUME From this brief review of the distribution of the known Upper Senonian fauna in South America and the West Indian region, a few generalities seem possible at this time. 1. In the most complete sections, two series of beds are present: (a) a lower series, usually more shaly and containing a fauna which is probably Campanian; (b) an upper series, more widely distributed, is usually formed of more shallow-water deposits, often reeflike or nonmarine in large measure or coarsely clastic. These beds are Maestrichtian. 2. The Upper Senonian transgression therefore commenced in the Campanian and reached its maximum expansion in the Maestrichtian but it was accompanied by uplift in the borderlands as is shown by the increasing coarseness of sedimentation in many areas, In other regions it was accompanied by volcanism. 3. The Peruvian Upper Senonian fauna is distinctly tropical in character and closely related to the North African. It seems also to be remarkably distinct from the Chilian and Patagonian faunas, the reasons for which are not yet clearly understood. BIBLIOGRAPHY
1. Iddings, A., and Olsson, A. A.
Geology of northwest Peru. Bull. Amer. Assoc. of Petroleum
Geologists, vol. 12, 1928, p. 9. 2. Gerth, H.
Neue faunen der oberen Kreide mit Hippuriten aus Nordperu.
Leidsche geol. Mededeel., deel 2, 1928, pp. 232-241. 3. Darwin, C.
Geological observations on the volcanic islands and parts of
South America visited during the voyage of H. M. S. ‘Beagle’,
Ist edition, 1844; 3d edition, 1891, pt. 2, 398, 399.
4. Gerth, H. Die pazifischen Transgressionen der jiingsten Kreide an der meee von Peru und Chile, Geologie Siidamerikas, vol. 2, 1935, p-. 9375.
187
=T
10.
11.
12.
13.
14.
15.
16.
17.
18.
NY),
CRETACEOUS OF PaAITA: OLSSON 29
Stille, H. Grundfragen der vergleichenden Tektonik, 1924, p. 156. Olsson, A. A. Tertiary deposits of northwestern South America and Pana- ma. Proe. 8th American Seientifie Congress, vol. 4, Geological Sciences, 1942, p. 281. Bailey, E. B. Sedimentation in relation to tectonics. Bull. G. 8S. A., vol. 47, 1936, pp. 1713-1726. Pettijohn, F. J. Archean sedimentation. Bull. G. 8. A., vol. 54, 1943, pp. 926- 969. Frizzell, D. Upper Cretaceous Foraminifera from northwestern Peru. Jour. Paleont., vol. 17, No. 4, 1943, pp. 331-353. dOrbigny, A. Voyage dans l’Amerique méridionale. Vol. 3, 1842, pt. 3, Geolo- gie, pt. 4, Paléontologie. Belcher, Lieut. The zoology of Captain Beechey’s vogage. London, 1859, p. 163. Forbes, E. Description of secondary fossil shells from South America. In Darwin’s Geological Observations. Appendix to Pt. 2, 1844, pp. 624-627. Philippi, R. A. Die tertidren und quartiren Versteinerungen Chiles. Leipzig, 1887. Steinmann, D., Deecke, W., Moricke, W. Das Alter und die Fauna der Guiriquina Schichten. N. Jahrb. Beil.._Bd. vol. 10, 1895, p. 1. A. Das Auftreten und Alter der Quiriquina-Sehichten. G.
Steinmann.
B. Uber Saurierreste aus den Quiriquina-Schichten. W. Doecke. C. Die Cephalopoden der Quiriquina-Schichten. G. Stein- mann.
D. Die Gastropoden und Bivalven der Quiriquina-Schichten. W. Moricke.
Wetzel, W. Die Quiriquina Schichten als Sediment und Paliéontologishes Archiv. Paleontographica, vol. 78, 1930.
Wilckens, O. Revision der Fauna der Quiriquina-Schichten. N. Jahrb. Beil. Bd., vol. 18, 1904. pp. 181-284.
Kossmat, F. The Cretaceous deposits of Pondicherri. Reeords, Geological Survey of India, vol. 30, pt. 2, 1897, pp. 72, 73.
Marshall, P. The Upper Cretaceous ammonites of New Zealand. Trans. New Zealand Institute, vol. 56, 1926, pp. 196, 197, 207.
Kilian, W., and Reboul, P. Les Céphalopodes néocrétacés des iles Seymour et Snow Hill. Wissenschaftl. Ergebnisse Schwed. Siidpolar-Expedition, 1901- 93, Band 38, Lief. 6, 1916.
30
26.
BULLETIN 111 188
. Stephenson, L. W.
The larger invertebrate fossils of the Navarro group of Texas. The University of Texas Publication, No. 4101, 1941, p. 38.
. Waring, G. A., and Harris, G. D.
The geology of the Island of Trinidad. B. W. I. The Johns Hopkins Univ. Studies in Geology, No. 7, 1926. Rutsch, R. Upper Cretaceous fossils from Trinidad. B. W. I. Jour. of Paleont., vol. 13, No. 3, 1939, p. 521. Maury, C. J. O Cretaceo da Parahyba do Norte. Servigo Geologico e Miner- alogico do Brasil, Monographia No. 8, 1930. MacGillavry, H. J. The rudist Fauna of Seroe Teintje Limestone (northern Cur- acao). K. Akad. Wetens. Amsterdam., Pr. vol. 35, 1932. p. 385.
. MacGillavry, H. J.
Geology of the Province of Camaguey, Cuba with revisional studies in rudist paleontology. Geog. en Geol. Meded., Phys- Geol. Reeks. Vol. 14, 1937.
Trechmann, C. T. The Cretaceous and Tertiary question in Jamaica. Geol. Mag., vol. 59, 1922, pp. 422-431. The Cretaceous limestones of Jamaica and their Mollusca. Ibid., vol. 61, 1924, pp. 2-19. The Cretaceous shales of Jamaica and their Mollusca. Ibid., vol. 64, 1927, pp. 27-42, 49-65.
. Hawkins, H. L.
Some Cretaceous echinoides from Jamaica. Geol. Mag., vol. 60, 1923, pp. 199-216.
Notes on a new collection of fossil echinoides from Jamaica. Tbid., vol. 61, 1924, pp. 312-324
28. Beuville, H.
Nouveaux Rudistes du Cretace de Cuba. Bull. G. 8. France, 4th serie, vol. 27, 1927, p. 50.
. Spath, L. F.
On Senonian Ammonoidea from Jamaica. Geol. Mag., vol. 62, 1925, pp. 28-32.
189 CRETACEOUS OF PAITA: OLSSON 31
SYSTEMATIC DESCRIPTIONS Phylum MOLLUSCA Class PELECYPODA Order PRIONODESMACEA Superfamily ARCACEA Family ARCIDZE Subfamily NQETINZE
Genus PSEUDOCUCULLAA Solger Pseudocucullea gregoryi Olsson Plate’ 2, figsy 1, 2 Pseudocucullea gregorui Olsson, 1934, The Cretaceous of the Amotape Region, Bull. Amer. Paleont., vol. 20, p. 22, pl. 3, fig. 1.
This remarkable species, first found at Monte Grande, is quite common in the Upper Breccia zone. It grew to a large size, the figured specimen measuring: length, 140 mm.; height, 134 mm., semidiameter, 47 mm. The hinge is known from several speci- mens but its finer details are generally obscured by a covering of matrix or damaged by breaks. The cardinal area is quite high, in the figured specimen it has a height of about 15 mm. just below the beak. It has a series of about eight, deep, ligamental grooves which are parallel to each side of the dorsal margin. The hinge plate is wide, solid, the central portion with a group of fine, narrow, lamellar teeth arranged transverse to the hinge margin and finely wrinkled or crenulated on their sides. The lateral teeth, two in number in each set, arg large and solid, the sides of the bordering sockets crenulated. Muscle scars were evidently deep but are not well exposed on any of our spec- imens. The external surface is smooth and there are no indi- cations of radial sculpture.
Figured specimen.—Paleontological Research Institution, No. 4820.
Occurrence.—Baculites zone.
Pseudocucullzea paitana, n. sp. Plate 2, figs. 3-5
Shell of medium size, obliquely subovate in form, highest in the posterior-ventral portion; the small beaks are placed at the
32 BULLETIN 111 190
C
anterior fourth and are separated from each other by the fairly wide, multivincular grooved, ligamental area; the anterior side is flatly rounded to subtruncate, the posterior side is obliquely rounded; the valves are moderately convex, when not crushed or distorted, with a fairly pronounced umbonal ridge extending from the beak to the junction of the ventral and posterior mar- gins; surface nearly smooth or roughened only by coarse lines of growth; hinge as typical for the genus; cardinal area as may be seen from the figure, is quite long, its height about one-seventh of its length and carrying a series of eight or more parallel, ligament- al grooves ; lateral hinge teeth strong.
Length, 73 mm. ; height, 71 mm.; diameter,.42 mm.
Length; 86.5 «hm.; height; 79 mm.; diameter, 4o emme (crushed)
Length, 76 mm.; height, 70 mm.; semidiameter, 25 mm.
This species is doubtless the fossil referred to by Gerth" as Cucullea, spec. nov. It is quite common in the ammonite beds at La Mesa. From Pseudocucullea gregory Olsson from Monte Grande and the Upper Breccia zone, this species differs by its smaller size and more oblique shell. Although abundantly rep- resented in our collection, none of our specimens have the hinge fully exposed.
Tvpes.—Paleontological Research Institution, Nos. 4821 4823.
Occurrence.—S phenodiscus beds of La Mesa.
4822,
J
Genus PERUARCA, new genus Genotype.—Peruarca pectunculoides, n. sp.
The following is a description of the genus Peruarca:
Shell subcircular to squarish; beaks nearly central; the hinge plate 1s of moderate width and curves down strongly at both ends ; hinge teeth forming a continuous series but divided almost equal-
1Gerth, H.: op. cit., ‘‘ Eine ganz neuartige Form fiir die wohl am besten eime neue Gattung geschaffen wird, da sie eine Art Mittelstellung zwischen Cucullea und Pectunculus einnimmt. Die grosse Muschel besitzt den raden, taxodonten Schlossrand mit ziemlich hoher Banderea und etwas nach vorne verschobenem und gekriimmtem Wirbel der ersten Gattune. Aber der Schlossrand ist erheblich kiirzer als die grésste Breite, die unge- faihr in der Mitte der um 1/8 hoher als breiten, stark gwolbten Klappe liegt., p. 239. ;
op- xe
191 CRETACEOUS OF PartTaA: OLSSON 33
ly into an anterior and a posterior set; in the middle, the teeth are small and transverse to the hinge line, they number about four on the posterior side and four or five on the anterior side; the lateral teeth are much larger, elongated and placed at first oblique to the hinge line but later become nearly parallel to it; the entire anterior set has about 14 teeth and the posterior set about 15; the cardinal area is of medium width, depressed, bor- dered by raised edges on the sides; a small triangular-shaped area just above the middle of the hinge and below the beak 1s faintly indicated by two diverging grooves which may corre- spond to a single pair of ligamental furrows; external sculpture of close, concentric lines and fine radials which show most strong- ly on the umbos ; margins entire.
Remarks.—This genus is proposed for a single left valve from the Baculites zone. The symmetrical hinge resembles that of Glycymeris but it differs from that genus by its plain cardinal area and externally by its form. From the members of the Trigonarca group, the main differences are the nearly complete absence of ligamental grooves and radial sculpture.
Peruarca pectunculoides, n. sp. Plate 3, fig. 6, 7 Shell of medium size, moderately convex with a nearly square
form, the height and length being about equal; anterior side is widely rounded, the posterior side nearly straight ; a well-marked umbonal angle extends from the beak to the posterior-ventral corner ; anterior, of the umbonal angle, the valve is smoothly con- vex while the posterior-umbonal slope appears flattened ; the sur- face sculpture is rather weak for the most part (partly the effects of weathering) except on the umbo and near the dorsal margin where it consists of fine, regular concentric ridges finely de- cussated by small, radial ribs; hinge as described above; inter- ior filled with matrix but the exposed margin of the valve is smooth.
Length, 50 mm.; height, 49.5 mm.; semidiameter, 19 mm.
Type.—Paleontological Research Institution, No. 4817.
Occurrence.—Baculites zone.
34 BULLETIN 111 192
Genus INCANOPSIS, new genus
Genotype.—Incanopsis acariformis, n. sp.
The following is a description of the genus /ncanopsis :
Shell small, convex with a sharply angled, umbonal ridge be- hind which the surface is strongly flattened or impressed; sculp- ture of fine ribs resembling that of Barbatia; beaks opisthogyrate, placed about one-third of the distance of the shell length from the anterior margins ; cardinal area wide, the longer part lying on the posterior side of the beak; the ligamental portion of the cardinal area is triangular in form, nearly equally divided between the anterior and posterior sides and marked off from the smooth parts of the cardinal area by deep lines; posterior portion of the cardinal area smooth; the ligamental grooves vertical; hinge plate long, narrow, with a continuous series of small taxodont teeth, coarser at the ends; ventral margin smooth; muscle scars plain.
Remarks.—The vertically grooved ligamental area and small episthogyrate beaks indicate a relationship of this small Creta- ceous ark with the Neetine. In the figured specimen, the liga- mental area forms a small triangle with a broad base and with the posterior side only a little longer than the anterior. It is sharply delimited from the remaining parts of the cardinal area (which is smooth) by deeply incised lines. The ligamental grooves are variable in coarseness and in the figured specimen number about 24. There are indications of very fine, vertical lines on the ligamental area which may correspond to the second- ary lines described by MacNeil? for some genera of the Tertiary Neetine. In the differentiation of the cardinal area into two parts, that of the ligament with its vertical grooving and the smooth posterior part, is comparable to that shown by the Eocene genus Scapularca but in other characters there is little resemblance between them. Through its Barbatia-like sculpture, as well as sharing a vertically striated ligament, /ncanopsis shows great simi- larity to Striarca Conrad (genotype Arca centenaria Say of the
2 MacNeil, F. 8.: Species and genera of Tertiary Naetine, U. 8. Geol. Survey, Prof. Paper No. 189-A, 1938, p. 7.
193 CRETACEOUS OF PaITA: OLSSON 30
Chesapeake Miocene). Striarca has recently been discussed by Schenck and Reinhart® and assigned by them to the Arcinee and not to the Neetinee as the transversely striated ligament and flanged muscle scars would seem to suggest. To this genus also, these authors have referred the Arca (Barbatia) @quilateralis Thiele (renamed Striarca thielei Schenck and Reinhart), a Recent species of the Dutch East Indies, although in that species, the ligamental area is reduced to a small triangular patch immediately below the beaks. Incanopsis acariformis, n. sp. IP eee) ah amos. al, AR ellen: i, anes Shell small, strongly convex, quadrate in form with a sharply angled umbonal ridge; sculpture subreticulate with numerous small ribs, finely nodulated by the concentric lines; these ribs may be more or less regular in size over the whole surface or much finer on the umbonal angle and on the posterior-dorsal submargins ; the valves sometime show a medial sulcation which is most strongly developed across the umbos; hinge and cardinal area as described above; ventral margin crudely crenulated. Length, 17.75 mm.; height, 10.5 mm.; semidiameter, 6.25 mm. Length, 23 mm.; height, 15 mm.; diameter, 14.5 mm. Types.—Paleontological Research Institution, Nos. 4832, 4833. Occurrence.—Lower zone at Tortuga; middle zone at Tortuga.
Genus BREVIARCA Conrad Breviarcea peruviana, n. sp. Rlaterss ese 25 oso
Shell small, rather solid, moderately convex, trigonal; beaks central; surface smooth but on magnification shows a sculpture of fine, threadlike, radial riblets which on the anterior-dorsal angle are finely decussated by the concentric lines ; cardinal area amphi- detic with symmetrical sides with respect to the beak and striated with fine, vertical lines; hinge plate narrow in the central part, wider and arched on the ends; hinge teeth numerous, prob- ably continuous, very small in the middle zone, much larger on
3 Schenck, H. G. and Reinhart, P. W.: The pelecypod genus Striarca from the Indo-Pacific Province, Archiv fiir Naturgeschichte, Bd. 7, Hft. 2, 1938.
36 BuLLetTiIn 111 194
the sides; anterior set has about eight teeth and the posterior set about 15; ventral margin smooth.
Length, 18.75 mm.; height, 15 mm.; diameter, 10.5 mm.
Length, 18.5 mm.; height, 14 mm.; diameter, 9 25 mm.
Length, 23 mm.; height, 18.75 mm.; semidiameter, 7 mm.
There are six specimens in the type collection. The species will be recognized by its trigonal form, central beaks and with the subumbonal area slightly more flattened than the anterior side. In our specimens, the hinge and cardinal areas are poorly pre- served but their chief characters are visible. The cardinal area is amphidetic, almost equally divided between the anterior and pos- terior sides. The ligamental portion is transversely grooved with fine lines which cover nearly the entire surface of the area except for narrow borders on the sides. The extent to which the liga- ment is developed to cover a small or a major part of the cardinal area is a variable feature amongst various species of Breviarca and consequently has small taxonomic value. In form, our shell resembles the more circular species of Breviarca such as B. perovalis Conrad and B. subovalis Stephenson*, but differs from them by its more trigonal, sharper beaks and longer, poster- ior end.
Types.—Paleontological Research Institution, No. 4814 (holo- type;) paratypes, No. 4815-4816.
Occurrence.—La Mesa.
Superfamily MYTILACEA Family MYTILIDA
Genus MYTILUS Linné
Mytilus signatus Olsson
Mytilus signatus Olsson, 1934, The Cretaceous of the Amotape Region, Bull. Amer. Paleont., vol. 20, p. 35, pl. 7, fig. 4.
This species is fairly common in the lower and middle fossil beds at Tortuga. It is characterized by its strongly flattened an- terior side which is sharply separated from the rest of the sur- face by an angled ridge. The entire surface is sculptured with
t Stephenson, L. W.: The Cretaceous formations of North Carolina, North Carolina, Geol. and Econ. Survey, vol. 5, pt. 1, 1923, pp. 110s aa pl. 20, figs. 1-8.
195 CRETACEOUS OF ParTA: OLSSON 37
fine, close-set, simple riblets except on the anterior area which is smooth, Septifer acutus Trechmann’ from Jamaica is very similar to our shell but ts larger. Specimen.—Paleontological Research Institute, No. 4872. Occurrence.—Tortuga. Genus VOLSELLA Scopoli
Volsella cerva, n. sp. Plate 17, fig. 8
Shell small, elongated, highest at the posterior end; beaks are near the anterior end and from which there extends a strong, umbonal ridge obliquely across the surface to the posterior-ven- tral corner; the sculpture is formed by radial riblets divided into two sets by a line along the top of the umbonal angle; on the dorsal or posterior side of the umbonal ridge, there are 11 strong, primary ribs which near the margin and on the ventral half be- come smaller and increase in number through intercalation; on the anterior side of the umbonal angle, the ribs are more num- erous and become progressively smaller towards the end; interior not known.
Length, 25.5 mm.; height, 16 mm.; semidiameter, 7 mm.
Type—Paleontological Research Institution, No. 4863.
Occurrence.—Tortuga.
Superfamily PTERIACEA Family VULSELLIDZ Genus PEDALION (Solander) Huddesford
Pedalion woodsi Olsson Melina woodsi Olsson, 1934, The Cretaceous of the Amotape Region, Bull. Amer. Paleont., vol. 20, p. 26, pl. 4,-fig. 1.
Two specimens of this species were collected in the lower fossil bed at Tortuga. One has the following dimensions: length, 69 mm.; height, 99 mm. The species was_ originally described from Monte Grande,
Specimen.—Paleontological Research Institution, No. 4871.
5 Trechmann, C. T.: The Cretaceous shales of Jamaica, Geol. Mag., vol.
64, No. 752, 1927, pp. 50-51, pl. 3, fig. 9.
38 BULLETIN 111 196
Occurrence.—Tortuga.
Genus GERVILLIA Defrance Gervillia incertans, n. sp. Plate 6, fig. 4
Shell elongate, convex; the beaks are placed near the anterior end; dorsal margin straight, forming the edge of the posterior wing; the posterior wing is rather long and quite wide and is differentiated by its more depressed, flattened surface; the shell itself is rather convex, the maximum inflation about the middle zone ; surface smooth; interior not exposed to view.
Length, 40 mm.; height, 17 mm.; semidiameter, 8 mm. (ap- proximate )
It has been impossible to expose the hinge structure and con- sequently the generic reference of this species to Gervillia is not certain. Its narrow form is somewhat similar to certain elongated Gervillias such as Gervillia aviculoides Defrance and Gervillia solentformis Defrance but is shorter and has a wider and longer wing. The contour of its anterior extremity is more suggestive of certain species of Volsella. Gervillia aviculoides has been figured by D’Orbigny in his Voyage of the Astrolabe (plate 7, fig. 37).
Type.—Paleontological Research Institution, No. 4845.
Occurrence-—Tortuga, lower zone.
Genus INOCERAMUS J. Sowerby Inoceramus, sp. A. Plate 1, fig. 2
This species is probably allied to the form figured by Stoliczka® as /noceramus Cripsianus Mantell from the Arrialoor group, the uppermost part of the true Cretaceous of south India. Stoliczka considered his specimens as agreeing with the form figured by Zittel’ as variety typica from the Gosau beds of central Europe. The Indian and Peruvian shells are characterized by their moderately large, strongly inflated, broadly subrhomboidal form with their greatest length lying in a zone extending through the middle and parallel to the dorsal and ventral margins. The
6 Stoliezka, F.: Cretaceous fauna of southern India, Paleontographiea Indica, vol. 3, 1871, p. 405, pl. 27, figs. 1, 1a.
7 Zittel, K. A.: Die Bivalven der Gosaugebilde in den nordéstlichen
Alpen, Denkschr. Akad. Wiss. Wien, vol. 25, 1865-66, p. 98, pl. 14, figs. 1, 2
197 CRETACEOUS OF PartTa: OLSSON 39
umbos are prominent and end in recurved beaks situated close to the anterior side. The sculpture is formed by widely spaced, concentric folds which are best developed on the central and anterior portions but become obsolete elsewhere.
Inocerami of somewhat similar characters to species A and B are common in the Upper Senonian rocks throughout the world. By most older workers, such as Zittel, Whiteaves, Stoliczka and Pervinquiére, these forms have been referred, as a group,. to Inoceramus cripsi Mantell but since typical cripsi is a species of restricted Cenomanian range, recent authors have used other names such as /noceramus regularis d’Orb., balticus Bohm, etc. The North African and European shells as well as most illus- trations of the North American forms differ by their wider, less convex valves, lower umbos and by their more persistant ribs.
Our specimen is an internal cast of a right valve with a frag- ment of the original shell retained along the dorsal margin. This specimen measures as follows:
Length, 110 mm. ; height, 76 mm. ; semidiameter, 40 mm.
Type.—Paleontological Research Institution, No. 4809. Baculites zone.
Occurrence. Inoceramus, sp. B Plate 1, fig. 1
This form is represented by an incomplete specimen of the left valve lacking the dorsal margin so that the beak and hinge char- acters are unknown. It is moderately convex but less inflated than species A. The form is broadly subovate. The sculpture consists of strong, persistant ribs of which about 15 are preserved. The ribs and their wide interspaces are crossed by a set of sub- obsolete, radial lines which simulate small ribs. These radials are strongest in the middle zone, elsewhere they may be faint or absent.
Amongst illustrated Inocerami, our specimen can be compared with Pervinquiére’s* figure of a North African shell determined as Inoceramus regularis d’Orbigny, but it is noticeably higher. There is, however, no close resemblance to D’Orbigny’s regularis
8 Pervinquiére, L., Etudes de paléontologie tunisienne: Pt. 2, Gastro- podes et lamellibranches des terrains Crétaces, 1912, p. 117, pl. 8, figs. 5-9.
40 BULLETIN 111 198
figured in the Paléontologie Francaise, Terrains Crétaces. An- other form allied to the Peruvian is possibly the Egyptian shell called Inoceramus cripsi Mantell var. radians by Quass® which shows strong radial markings in the interspaces of the ribs over the entire shell.
Our specimen measures:
Length, 110 mm.; height, 90 mm ; semidiameter, 30 mm.
Type.— Paleontological Research Institution, No. 4810.
Occurrence.—Baculites zone.
Superfamily ANOMIACEA Family ANOMIIDA® Genus ANOMIA (Linné) Miller Anomia, sp.
There are several small Anomias in the lower fossil beds at Tortuga but our specimens are too imperfect for identification or illustration. They belong to three species. Some have a smooth surface and the free valve is nearly circular in form with the small beak removed slightly from the edge of the dorsal margin. Another form has a larger shell with widely spaced concentric lines while a third species has a sculpture of small raised pustules.
Occurrence.—Tortuga, lower fossil bed.
Superfamily OSTREACEA Family OSTREIDAE
Ostrea palpa, n. sp. Plate 1, figs. 5, 6; Plate 4, figs. 8, 10
Shell small, irregular in form and sculpture but the left or at- tached valve is generally larger, more convex and more strongly ribbed than the right; the left valve is irregularly rounded to elon- gate in form with the sides generally impressed and the beaks turned to the left if not obliterated by the large attachment scar; the ribs of the left valve are typically large and strongly developed in the middle zone, absent from the sides and generally become obsolete on the older shells; right valve is smaller, more rounded,
9 Quass, A.: Die Fauna der Oberwegischichten und der Blitterthone in der libyschen Wiiste, in Beitrag zur Kenntniss der Fauna der obersten Kreidebildungen in der libyschen Wiiste, Paleontographica, Band 30, Ab- teil 2, 1902, p. 170, pl. 20, figs. 9, 10.
199 CRETACEOUS OF PAITA: OLSSON 41
flatter and unribbed but with more pronounced concentric mark- ings; the posterior side of each valve is generally expanded or winged ; interior of the left valve with a grooved, crenulated mar- gin and a narrow, curved, ligamental furrow which ends in the tip of the beak; the interior of the right valve is less deep and the ligament furrow is wider and the margins of the valves have short ribs which form the crenulated pits in the grooved margins of the left valve.
Length, 19.5 mm.; height, 29 mm.; semidiameter, 14 mm. (left valve).
Length, 14 mm. ; height, 25 mm.; diameter, 13 mm.
Length, 16 mm.; height, 20 mm.; diameter, 13 mm. (holo- type).
This species is common in the lower zone at Tortuga. It is associated with larger, thinner shells which are probably Anomias but their interiors have not been seen. The- crenulated margins of this small oyster recalls some early Eocene species.
T ypes.—Paleontological Research Institution, holotype, No. 4805 ; paratypes, Nos. 4800-8.
Occurrence.—Tortuga.
Subgenus LOPHA Bolten
Ostrea (Lopha) sechura, n. sp. Plate 1, figs. 7, 8
Shell of medium size, solid, broadly sickle-shaped as figured; surface sculpture of the left valve is formed by 11 or 12 strong ribs which on the lower or ventral portion are enlarged and an- gular in form; posterior umbonal side deeply inflexed, its sur- face sculptured with fine, narrow riblets and its valve margin coarsely crenulated ; interior of left valve is relatively shallow, its anterior and ventral margins coarsely fluted by the ends of the ribs; muscle scar of medium size and outlined by thickened margins.
Height, 88 mm.; width, 68 mm.; semidiameter, 29 mm.
Only the left valve is known but the species will be easily rec- ognized by its sculpture and broad, sickle form.
Ostrea (Lopha) stappenbecki Olsson occurs at Tortuga but
42 BuuLuetTin 111 200
only fragments are available in our present collections. T ype.—Paleontological Research Institution, No. 4804. Occurrence.—Baculites zone.
Superfamily TRIGONIACEA
Family TRIGONIIDA
Genus TRIGONIA Bruguiere Subgenus SCABROTRIGONIA Deecke Trigonia (Scabrotrigonia) gerthi, n. sp. Plate 3 figs. mo neo
Trigonia crenulata Peruana Gerth (not Paulcke), 1928, Neue Faunen der Oberen perenle mit Hippuriten aus Nordperu, Leidsche geol. Mede- deel, Deel 2, p. 234. ;
The shell is thick, moderately convex with a hatchet-shaped form and well-rounded, ventral margins; the umbones are small with incurved, opisthodetic beaks placed near the anterior end; the sculpture consists of a set of strong, coarsely scabrous ribs numbering about 23 which cross the surface of the valve from the ventral margin to the edge of a smooth zone extending from the beak to the posterior-dorsal margin; on the anterior side, the liinule is poorly defined by a shallow groove and by the more 1r-
regular form of the ribs; the escutcheon is outlined by its more depressed surface and by a sculpture of small, scabrous riblets trending transverse to the dorsal margin; between the escutcheon and the main sculptured disk, is an unribbed band extending from the beak to the posterior-dorsal margin; this band is divided by a groove into two equal parts; in the region of the umbo, this band is cordlike and sculptured by the end of the ribs extending from the shell disk and from the sides of the escutcheon, more pos- teriorly, the band widens and becomes smooth except for the
coarse lines of growth. Length, 52.5 mm.; height, 43 mm.; semidiameter, 13.75 mm. Length, 56 mm. ; height, 46 mm. ; semidiameter, 17 mm. (type) Length, 63 mm. ; height, 57 mm.; semidiameter, 26 mm. This species resembles Triyonia scabra Lamarck by its sharply scabrous, narrow ribs but differs greatly from that species by its
201 CRETACEOUS OF PaAITA: OLSSON 43
form and in the sculpture of its posterior-dorsal area in which respect it approaches the Tyrigonia crenulata Lamarck, In Trigonia crenulata and its allied subspecies tocaimaana Lea (subcrenulata d’Orb.), the ribs are corded or crenulated and in the South American forms fewer in number. Perhaps more closely allied to our shell, is the Trigonia bartrami Stephenson’? from the Exogyra ponderosa zone in North Carolina but it seems to differ by its more widely spaced ribs. There are specimens of a small Trigonia at La Mesa but they are too poorly preserved to be identified.
Types.—Paleontological Research Institution, holotype, No. 4812; paratype No. 4813.
Occurrence.—Baculites zone.
Trigonia hopkinsi, n. sp. Pilates. ties
Shell large, thick, subrhomboidal to hatchet-shaped; umbos high, projecting above the hinge line and sculptured with strong ribs ; beaks small, nearly touching each other and situated a little in front of the middle axis of the valves; anterior side of the valves is widely rounded, the curve passing evenly into the ven- tral margin; posterior side is straight, appearing as if truncated, slightly oblique; convexity of valves moderate; the sculpture is mainly restricted to the umbos which have a series of strong, riblike folds which fade out on the middle zone of the valves and on the posterior area; the ribs on the posterior side are smaller, shorter, and curve sharply towards the margins; the main sur- face of the valves is smooth or roughened only by the lines of growth; a strong umbonal angle extends from the beak to the corner between the ventral and posterior margins; interior not known.
Length, 98 mm.; height, 92 mm.; semidiameter, 24 mm.
Length, 80 mm.; height, 71 mm.; diameter, 43 mm.
This unusual Trigonia is distinguished by its large, quadrate form and in having only the umbos and the adjacent portions of the posterior-dorsal submargins strongly sculptured, the remain-
10 Stephenson, L. W.: Cre‘aceous formations of North Carolina, North
Carolina Geol. Econ. Sur., vol. 5, pt. 1, 1923, p- 186, pl. 52, figs. 1-3; pl. 53, figs. 1-4.
44 ; BuLuETIN 111 202
ing area of the valves being smooth. The Trigonia Sieversi Steinmann’! is somewhat similar to the young of this species but judging by the figure given by Steinmann in his Geologie von Pert, its sculpture is finer on the anterior portion and the form is even more quadrate. A very small Trigonia, only .7 cm. in length from the lower Senonian of Huallanca, Peru, was de- scribed by Briiggen?? as Trigonia parva. This shell has the quadrate form and strong ribbed sculpture of Trigonia sieverst and may be the young of that species. T ype—Paleontological Research Institution, No. 4819. Occurrence.—Baculites zone., Order ANOMALODESMACEA Superfamily ANATINACEA Family LATERNULID® Genus ANATIMYA Conrad Anatimya, sp. Plate 6, figs. 5, 6 The material of this form from Tortuga is badly crushed but its reference to the genus Amatimya seems reasonably certain. The shell is very thin and in most specimens, only small pieces of the original shell remains. The form is elongate, the beaks placed slightly anterior of the middle. The internal cast shows a series of small ribs in the central zone but the sides are smooth. Specimens.—Paleontological Research Institution, Nos. 4850, 4851. Occurrence.—Tortuga middle zone. Family PERIPLOMIDZ z
Genus PERIPLOMA Schumacher aes
Periploma nermeta, n..sp. Plate 3, fig. 3 Shell of medium size, inequivalve, thin, subelliptical in form; anterior side is well rounded and twice as long as the posterior which is narrowed and was probably subtruncated at the end (broken in the type); the left valve is flat, depressed or flexed slightly in the central, anterior region; right valve is moderately convex, greatest in the zone extending from the beak to the an- terior-ventral margin; surface is smooth, marked only with lines of growth with indications of resting marks which produce a
11 Steinmann, G.: Geologie von Pert, He ‘idelberg 1929, p. 175, fig. 225. l2 Briiggen, H.: Die ee ones n und Lamellibranchier des unteren senons von Nord-Peru, N. J. f. Min. ete., BB., vol. 30,1910, taf. 25, fe az.
oma
203 CRETACEOUS OF PAITA: OLSSON 45
roughly banded appearance; granules or pustules are present on the posterior subzone in the left valve (this area is destroyed on the right valve) ; beaks destroyed on the type specimen but there are remains of a buttresslike structure which may have served as support for the chondrophore,
Length, 66.5 mm.; height, 44 mm.; diameter, 13. mm.
From the form of the valves alone, the fossil would appear to belong to Periploma without question. The beaks have been destroyed by weathering but reveal a sandy matrix filling the interior and the remains of a solid structure which was probably the support for the chondrophore. The anterior portions of the valves is largely destroyed but remains indicate a flexed zone such as is characteristic of most species of this genus. Coarse, irregular pustules are sparingly distributed over the whole sur- face and are strongly developed on the anterior subzone of the left valve.
Type.—Paleontological Research Institution, No. 4818.
Occurrence.— Baculites zone.
Order TELEODESMACEA Superfamily CYPRICARDIACEA
Family PLEUROPHORIDE Genus ROUDAIREIA Munier-Chalmas
Roudaireia peruviana Olsson Plate 2, figs. 6, 7
Roudairecia jamaicensis peruviana Olsson, 1934, The Cretaceous of the
Amotape Region, Bull. Amer. Paleont., vol. 20, p. 42, pl. 2, fig. 6.
Gerth recorded Roudaireia Drui (=auressensis) from the Paita region but in our collecting we have found only the larger and smoother peruviana which is common in the Upper Breccia zone. Our largest specimen, a right valve measures length, 91 mm.; height, 86 mm.; and diameter, 46 mm. The anterior side of the umbos are sculptured over a small area with strong ribs which fade out before reaching the umbonal angle. The general surface of the shell is smooth except where the concentric growth lines become coarse and crowded together during resting periods.
Specimens of Roudaireia from the Austrosphenodiscus beds are too much wind eroded to be specifically identified but their
46 BULLETIN 111 204
shape and sharply angled, posterior ridge is more like perwviana than the ribbed auwressensis. Briiggen’s Roudaireia intermedia™® is a small shell of about 30 mm. in length and height and is listed from Otusca near Cajamarca together with Coniacian ammonites. A coarsely sculptured species resembling a small auwressensis has been described by Lisson'! as Roudaireia briiggent. Its age is Lower Senonian.
Specimens figured.—Paleontological Research Institution, Nos. 4824, 4825.
Occurrence.—Baculites zone. Austrosphenodiscus beds at
La: Mesa: Genus GLOSSOCARDIA Stoliczka Subgenus TORTUCARDIA new subgenus Genotype.—Glossocardia (Tortucardia) stephensoni, n. sp.
The following is a description of the subgenus Tortucardia:
Shell elongate, of an irregular form, with an aneled umbonal ridge, smooth except for irregularity in the lines of growth; hinge with three cardinal teeth in the left valve, two in the right; a dis- .tant posterior lateral tooth but no anterior lateral; ligament ex- ternal.
Remarks.—From Glossocarcia Stoliczka, genotype Glosso- phora obesa Reeve, a Recent species from Mauritius, this group differs in possessing three cardinal teeth in the left valve. The shape of the shell is very variable, perhaps due to a burrowing
habit but most of our specimens have been strongly distorted.
Glessocardia (Tortucardia) stephensoni, n. sp. Plate 17, figs. 5-7
Shell of medium size, irregularly subrectangular in outline, equivalve and strongly inequilateral; beaks situated near the anterior end; a strong, angular umbonal ridge extends obliquely from the posterior side of the beak to the posterior-ventral mar- gin; the beaks are small, prosogyrate, nearly touching each other and situated fairly close to the anterior side, above them the umbos are wide and bordered on the posterior side by an
18 Briggen, H.: Die Gastropoden und Lamellibranchier des Senons von Nord-Perti, N. Jahrb. Min. ete., BB. vol. 30, 19110; p 26, fig. 2.
14 Lisson, C. I.: Boletin de la Sociedad Geologica del Pert, 1925, p. 28, lamina 3, figs. 6, 7, 8.
unteren 5 1G, oll
tomo 1
?
205 CRETACEOUS OF PAITA: OLSSON 47
angle; medially, the shell develops a shallow, sometimes scarcely noticeable furrow which widens ventrally; sculpture consists of coarse, concentric growth lines which are strongest on the an- terior side, smoother on the umbonal ridge; escutcheon narrowly linear; the hinge has three cardinal teeth in the left valve, two in the right; the posterior lateral is distant and there are no an- terior laterals; the cardinal teeth are enlarged or nodulose at the end; a long lamelle (which may be the nymph) lies above the cardinal teeth along the dorsal margin and above which is the external ligament.
Length, 28 mm.; height, 18 mm.; diameter, 14 mm.
Length, 31 mm.; height, 17.25 mm. ; semidiameter, 9 mm.
Length, 30 mm. (broken); height, 20 mm.; semidiameter, 10 mm.
The shell is rather variable in form, perhaps the result of a burrowing habit, but most of my specimens have been distorted during fossilization.
Types.—Paleontological Research Institution, Nos. 4864, 4865, 4860.
Occurrence.— Tortuga.
Superfamily SPHZERIACEA Family CORBICULIDZ
Genus CORBICULA Megerle von Miihlfeld Corbicula meridionalis, n. sp. Plate 4, figs. 3, 4
Shell is nearly circular in outline, moderately convex and relatively thin; the anterior, ventral and posterior sides form together a nearly complete circle, with the dorsal side narrower and more straight; umbos are prominent, ending in the small, opisthogyrate beaks, placed at the anterior third; interior cavity of the valves is not known, being filled with matrix in all speci- mens; the hinge of the right valve has the following characters: the hinge plate is narrow and elongated; beneath the beak, there are three, small, cardinal teeth, the middle one being double, the other two are long and narrow; the posterior lateral tooth is distant, long, narrow, bordeted above by a groove for the inser- tion of the posterior, left lateral; anterior lateral not preserved in the specimen but in a left valve it is placed about half as far
48 BULLETIN 111 206
from the beaks as the posterior lateral; surface smooth or marked with growth lines which are coarse and strong in the small area just below the beaks; in some specimens, faint, radial strie, resembling those of some Diplodontidee are present ; no lunule. Length, 37 mm.; height, 31.5 mm.; semidiameter, 9.5 mm. Externally, this species resembles a Cyclinella, the shell being nearly circular in form and very thin. Most of the specimens are broken or crushed and molds of the interior show no markings of the pallial line. The hinge is quite similar to Fgetaria pullastra Morch but the anterior lateral is more distant. Types.—Paleontological Research Institution, Nos. 4834, 4835. Occurrence.—Tortuga, middle zone.
Superfamily RUDISTACEA Family RADIOLITIDZE Genus SAUVAGESIA Bayle, sensu lato Sauvagesia peruviana, n. sp. Plate 8
Sphaerulites (Lapeirousia) ef. nicholasi Olsson, 1934, The Cretaceous of the Amotape Region, Bull. Amer. Paleont., vol. 20, pp. 49, 50, ph 8, fig. 4. Not of Whitfield, 1897.
Fragments of this large rudistid from Monte Grande were referred provisionally to Whitfield’s Sphaerulites nicholast from the Upper Cretaceous of Jamaica, the forked, vascular markings of its separated wall plates being very similar. More perfect specimens from Tortuga, since available, show that the Peruvian form is a distinct species and may belong even to a different genus. All the specimens are fragments of the lower or attached valve. Our largest example, the holotype, consisting of two pieces, has a diameter of about 1314 inches. The smaller specimens are often colonial and may perhaps belong to a species different from the larger form, It appears as if the Peruvian species cannot be assigned to any described genus. Lacking perfect specimens, I am for the present referring the form to the genus Sauvagesia in a broad sense.
The lower valve is thick, ponderous and spread broadly up- wards from a basal or apical attachment point, and as shown by some smaller colonial specimens, its spreading edges were lobed or star-shaped. The external surface is in most cases de- stroyed by weathering but in one small specimen it is seen to have
207 CRETACEOUS OF ParTA: OLSSON 49
been coarsely striated or ribbed. The texture of the outer layer is very thick and composed of fine lamella with the surface of each thin layer marked with fine wrinkles or granules and crossed by large, forked vascular furrows; these vascular markings show- ing as elevated ridges on the lower side of each lamellar layer. The visceral cavity is a hollow cone, generally wide and shallow at the top but prolonged into a long, crooked tube below. The inner shell layer which forms the lining of the cone or visceral cav- ity is smooth or marked with fine, parallel lines conforming to the lamellar layers of the outer wall. Its color is brown or darker than that of the outer shell. The walls of the cone are smooth except where broken by fractures and show no internal rib or flexure indicating the position of the ligament and the channels for the siphons.
The most prominent characters of the Peruvian rudistid are its low, spreading form and simple visceral cone. A similar type of growth form is assumed by Dania curasavica Martin from the Seroe Teintje limestone of Curacao and referred by MacGil- lavry’ to the genus Durania Douville. The Curacao species ap- pears to attain great size, specimens about 300 mm. are said to be common. The species has also been recorded by the same author’® from Loma Yucatan, Camaguey Province, Cuba, where if occurs with its characteristic flat form and large size in com- pany with other rudistids. Both Trechmann and Mac Gillavry have noted the very flat cone of the Curacao species and sug- gested the possibility that it constituted a new genus. Durania, as exemplified by its genotype, the Hippurites cornupastoris Des Moulins’ has a high, stout form with a coarsely ribbed surface and the siphonal channels are marked by two strong, longitudinal
15 MacGillavry, H. J.: The rudist fauna of Seroe Teintje limestone (northern Curacao), K. Akad. Wetens. Amsterdam., Pr. vol. 35, 1932, p. 380, pl. Ie figs”, 8: pl. 2, figs: 1-6:
16 MaceGillavry, H. J.: Geology of the Province of Camaguey, Cuba with revisional studies in rudist paleontology, Geog. en Geol. Meded., Phys-Geol. Reeks, vol. 14, 1937, p. 42
17 For good figures see Toucas, Ar.; Etudes sur la classification et l’évolution des Radiolides, Soe. Geol. France, Mem. Paleon., n. 36, vol. 17, 1909, p. 94, pl. 3.
50 BULLETIN 111 208
furrows. These characters are very different from any shown by peruviana. Radiolites nicholasi Whitfield is apparently con- sidered a Bournonia by MacGillavry but further checking seems necessary. Fragments of a radiolite showing vermiculate mark- ings were collected from the Act@onella-Pironea limestone at La Mesa but are insufficient for identification. Types.—Paleontological Research Institution, Nos. 4800-4803. Occurrence.—Uppermost sandstones at Tortuga.
Superfamily CARDIACEA
Family CARDITD® Genus CARDiIUM Linneé Cardium (?) abnormalis, n. sp. Plate 17, fig. 3
The shell is of medium size with a Fragum-like form and a thick, solid texture; umbo high, wide, ending above in a small prosogyrate beak; umbonal ridge high, angled, the dorsal-pos- terior area well defined and divided by a groove in the middle, the outer portion being flattened while the inner or side next the hinge being arched or vaulted; a deep furrow or groove extends from the ventral margin upwards towards the beak but is only faintly indicated on the umbo; surface is smooth except for ir- regularly distributed growth lines which at intervals are grouped together in resting marks; ventral margin crenulated; hinge un- known.
Length, 32 mm.; height, 36 mm.; semidiameter, 17 mm,
The type of this species is a single left valve with the hinge completely covered with a hard, cemented matrix which cannot be removed. Although its form is so unusual, there are some features of the shell which suggest that the species belongs to the Cardiide. The strong, umbonal ridge and the well-differen- tiated medially divided, posterior-dorsal area are similar to Fragum. The surface appears to have been smooth or marked only with irregular growth lines which are occasionally crowded together to form resting marks, a type of surface ornamentation similar to Pachycardium. The ventral margin is strongly thick-
209 CRETACEOUS OF ParTa: OLSSON 51
ened and internally crenulated. Whether the deep groove is a normal feature or merely a shell fracture cannot be determined from this specimen.
Type.—Paleontological Research Institution, No. 4862.
Occurrence.—Baculites zone.
Subgenus PERUCARDIA, new subgenus Genotype.—Cardium (Perucardia) briiggeni, n. sp.
The following is a description of the subgenus Perucardia:
Shell large, inflated, subcircular; ribs numerous, their inter- spaces rectangularly grooved; ribs adorned with short spines and strong nodes or granules, their interspaces being smooth; liga- ment external, seated on a large, thickened, nymphal plate; hinge strong, the dentition normal; the right valve has two, strong cardinals which are fused and form the posterior side of a deep socket; in the leit valve, the cardinal teeth are free, the anterior one very large, the posterior one much smaller, vertical and placed above the socket, its upper end almost touching the beak ; lateral teeth strong, each situated at an equal distance from the cardinals.
Remarks.—Perucardia resembles Trachycardium Morch but differs by the character of the nodes ornamenting its ribs which are simple granules, sometimes greatly enlarged and not the roofed, scalelike spines of the latter genus. From Granocardium Gabb, which it resembles by its rounded, inflated form, it differs in having the nodes seated on the summit of the ribs and not in their interspaces. These nodes are present over the entire shell and on the anterior ribs are greatly enlarged and closely crowded. They are generally small on the central ribs, only their bases being generally preserved. Over most of the surface, the nodes on each fifth rib are larger than the adjacent ones. The hinge is normal and amongst Recent species is most similar to that of Mexicardia Stewart, as illustrated by its West Coast species, Cardium procerum Sby.
52 BULLETIN 111 | 210
Cardium (Perucardia) briiggeni, n. sp. Plate 5) fics lessee
Cardium, ef. Lissoni Olsson, 1934, The Cretaceous of the Amotape Region, Bull. Amer. Paleont., vol. 20, p. 52, pl. 5, fig. 3 (mot of Bruggen, 1910).
Shell large, subcircular, ventricose, moderately thin in the umbonal portion, thicker elsewhere; the umbos are very wide, inflated, with beaks placed nearly centrally, coiled and nearly touching above the hinge line; the outlines of the valves is sub- circular, the sides well rounded, the posterior, a little longer than the anterior; there is no defined dorsal area; the ribs are nu- merous, an exact count not being possible from the available material but probably number about 60; due to weathering and decortication of the surface, the ornamentation of the ribs is gen- erally preserved only on a portion of the shell, the ribs being plain on most specimens; the ribs were originally adorned with large and small nodes or spines; these nodes on the anterior ribs form large knobs but on the central ribs are small, toothlike spines, there is a general tendency for these nodes or spines to be larger on each fourth or fifth rib, especially on the margins; hinge as described above; margins fluted in harmony with the ribs; ap- proximate size of a large specimen would be: length, 102 mm. ; height, 106 mm. ; semidiameter, 45 mm.
Decorticated specimens of this species from Monte Grande were first referred to Bruggen’s'® Cardium lissoni, a species de- scribed from the Lower Senonian of Peru. The present species differs from C. lissoni by its ornamented ribs. Cardium briiggeni appears to be a widely distributed species in the Maestrichtian of South America. We have specimens from Colombia and Ven- ezuela.
Types.—Paleontological Research Institution, Nos. 4827, 4828, 4829.
Occurrence.—Baculites zone. Monte Grande. La Mesa.
18 Briiggen, H.: Die Gastropoden und Lamellibranchier des wnteren
Senons von Nord-Pert, N. Jahrb. Min., ete. BB., vol. 30, 1916, p. 756, pl. 26, sifed, die
211 CRETACEOUS OF ParTaA: OLSSON 53
Subgenus INCACARDIUM, new subgenus
Genotype.—Cardium (Incacardium) mellisum, n. sp.
The following is a description of the subgenus /ncacardium :
Shell elongate-subcircular, the posterior side pointed, with a deeply impressed zone extending from the beak to the ventral margin; nymphal plate small; cardinals unfused and situated mid-~ way between the fairly distant laterals; ribs numerous, triangular in section and ornamented with scattered fluted or scalelike spines.
Remarks.—By its elongated and. pouting posterior extremity, this Cardium resembles certain ribbed Liopistas but has a thicker shell and different hinge. The ribs on the middle area and on the anterior sides have a rasplike appearance because of the sharp, fluted or scalelike spines. The hinge is fairly normal and is gen- erally similar to that of Trachycardium to which group, this subgenus is probably closest related. The cardinal teeth of the right valve, the only one well known, are perfectly free at their upper ends; and the anterior tooth, although smaller than the pos- terior, is still quite large and is placed obliquely to the direction of the hinge line. The laterals are quite strong and equidistant from the cardinals. Cardiuwm caudatum dOrbigny™ as figured in the Voyage of the Astrolabe has a shape similar to /ncacardiuwm but the posterior-dorsal area is shown as smooth or unribbed. The species has not been recorded by subsequent workers and is possibly a Liopista.
Cardium (Incacardium) mellisum, n. sp. Plate-5, figs. 2; 45-6
Shell of medium size, convex and sculptured with scaled or spine-bearing ribs; the valves are moderately convex, the great- est inflation being located just posterior of the middle line; a deeply impressed zone extends from the beak to the posterior- ventral margin; it is bordered on the posterior side by the dorsal area which appears somewhat flattened and has a smoother, ribbed sculpture; the sculpture is formed by numerous ribs of triangular section, arranged as follows:—in the middle and an-
19 d’Orbigny, A.: Voyage au Pole Sud et dans l’Ocednie sur les cor- vettes L’ Astrolabe et La Zéleé, Geologie Atlas, 1847, figs. 25, 26.
54 BULLETIN 111 21:2
terior sides, the ribs number about 22, in the depressed zone about six and there are six or seven on the dorsal area; these ribs are largest in the central part and are adorned with scattered fluted or scalelike spines placed on the summits; the interspaces are triangular in form, smooth or etched with cross lines; the ribs of the depressed zone and the dorsal area are smaller and plain; a small area on each side of the beaks is smooth; hinge plate narrow, the right valve has two, unfused, cardinal teeth, the posterior one larger and bordering a V-shaped socket ; lateral teeth strong and situated at an equal distance on each side of the cardinals ; inner margins fluted by the ends of the ribs.
Length, 34 mm.; height, 29.5 mm.; semidiameter, 13 mm. (ho- lotype).
Length, 37.5 mm.; height, 30.5 mm.; semidiameter, 17 mm.
T ypes.—Paleontological Research Institution, Nos. 4830, 4831.
Occurrence.—Tortuga, middle zone. La Mesa.
Superfamily VENERACEA
Family VENERIDA® Genus APHRODINA Conrad
Aphrodina pacifica, n. sp. Plate W-fiesaeleme
The shell is large, thick, subelliptical and moderately convex ; beaks prosogyrate, approximate, situated about a fourth of the shell length from the anterior extremity; umbonal — slope rounded; lunule cordate to subelliptical in form, in length about three-fourths of the distance between the tip of the beak and the anterior basal margin; right valve with a wide hinge plate on which are placed three cardinal teeth and a corrugated pit or socket for the anterior left lateral, the nymph is marked off above by a deep groove; the surface is smooth or irregularly wrinkled by the concentric growth lines; escutcheon is not defined.
Length, 66 mm. (imperfect) ; height, 61 mm.; semidiameter, 20 mm.
The holotype is a specimen of the right valve showing the hinge but the cardinal teeth are damaged. The hinge of the right valve has the anterior lateral socket strongly pitted or corrugated.
or or
213 CRETACEOUS OF PATTA: OLSSON
This hinge is similar to that figured by Stephenson?" for the geno- type of Aphrodina, the Aphrodina tippana Conrad of the Upper Cretaceous of the Atlantic and Gulf coasts. Our species is most similar to 4 phrodina regia Conrad from the Upper Cretaceous of North Carolina, differing principally by its more anteriorly placed beaks. Type.—Paleontological Research Institution, No. 4857. Occurrence.—Baculites zone. Aphrodina cf. auca d’Orbigny
Antigona, sp., Olsson, 1934, The Cretaceous of the Amotape Region, Bull. Amer. Paleont., vol. 20, No. 69, p. 54, pl. 5, fig. 6.
Shell is small or medium-sized, solid, rounded and moderately convex ; the small beaks are placed at the anterior one-third and are closely adjacent and curved over the small, flattened or fee- bly arched lunule ; umbos are wide and full, and appear somewhat flattened; posterior-dorsal slope curved and strongly arched in the middle; the margin along the base and at the anterior and posterior sides is well rounded; lunule is large, flattened, limited by a groove; left valve has a heavy hinge plate on which is placed an anterior lateral tooth, wrinkled or corrugated on the sides, to- gether with three cardinal teeth, the upper one bordered by a shallow, slightly rugose furrow; surface of shell sculptured with strong, even, concentric ribs which cover the entire surface or become reduced to irregular wrinkles on the sides. The size is rater variable, an average measurement is length, 37 mm.; height, 32 mm.
On the basis of Wilcken’s*! figure of Cytherea auca d’Orbigny, 1847, I am referring our fossil to the Chilian Cretaceous spe- cies currently identified by this name, with the reservation that an actual comparison of specimens might reveal differences not at present evident from the figures alone. True Venus auca 29 Stephenson, L. W.; Invertebrate fossils of the Upper Cretaceous formation, North Carolina Geol. Econ. Sur., vol. 5, 1923, p. 314, pl. 71, figs. 4 and 6.
21 Wilekens, O.: Revision der Fauna der Guwiriquina-Schichten, N. Jahrb. Min. ete., BB. vol. 18, 1904, pp. 243-248, pl. 19, figs. 12-14.
22 d’Orbigny, A.: Voyage au Pole Sud et dans l’Océanie sur les cor- vettes L’ Astrolabe et La Zéleé, Geologie Atlas, 1847, pl. 5, figs. 9, 10.
56 BULLETIN 111 214
d@’Orbigny, 1842,2% as noted by several authors (Stoliczka,”*
Wilckens) is a Tertiary Tapes-like shell and the name auca should not be used for the Cretaceous species. Through various mutants of the fossil, many based on casts, the species has often been renamed by Philippi according to the extensive syn- onymy given by Wilckens, Therefore a decision as to the proper designation of this common Chilian Cretaceous species must be reserved for some student working directly with Chilian collec- tions. Occurrence.—Baculites zone. ‘Tortuga.
Aphrodina speciosa, n. sp. Plate 4, figs. 5-7
Shell small or medium-sized, with convex whorls and a sub- ovate form; umbos wide, prominent ending in small, slightly coiled beaks placed at the anterior one-fourth ; sculpture is formed by quite strong, concentric ribs which have a subequal spacing on the center of the disk but become irregular near the ventral mar- gin and are much smaller, closer spaced on the umbos; no es- cutcheon, the umbonal slope being strongly convex; lunule cor- date, quite large and defined by an incised line across which the concentric sculpture passes with no change; interior and hinge not known.
Length, 21 mm.; height, 19 mm.; diameter. 13 mm.
Length, 18.5 mm.; height, 16.5 mm.; diameter, 11 mm.
Length, 16 mm-; height, 15, mim; diameter, 11 man
This species is usually small, the average size being about 18 mm. but an occasional individual may reach 24 mm. _ The shell is strongly convex, its texture solid and the surface sculptured by strong, subequal ribs which have a convexly curved form con-
23 d’Orbigny, A.: Voyage dans l’Amerique meridionale, Pal., 1842, p. 122, pl. 12, figs. 17, 18.
24 Stohezka, F.: Cretaceous faunas of southern India. Peleeypoda, 1865-70, p. 165, No. 184.
215 CRETACEOUS OF ParTA: OLSSON 57
centric to the strongly rounded ventral margin. Interior and hinge have not been seen.
Types.—Paleontological Research Institution, holotype, No. 4836; paratypes, Nos. 4837, 4838.
Occurrence.—Tortuga, lower fossil bed.
Subgenus SECHURINA, new subgenus Genotype.—A phrodina (Sechurina) australis, n. sp. The following is a description of the subgenus Sechurina: Shell large, solid and with a hinge structure essentially simi- lar to that of Aphrodina but differs in having a well-marked escutcheon defined by a change in sculpture and by a deeply im- pressed line.
Aphrodina (Sechurina) australis, n. sp. Platewieitcsees,. os (6
Shell large, thick, convex, subovate to subelliptical in form; umbos wide and prominent, the beaks prosogyrate, approximate and situated about a fourth of the distance from the anterior ex- tremity; posterior extremity subtruncated; escutcheon narrowly elliptical, marked off by a strongly angled ridge and bordered ventrally by a deeply incised line ; lunule broadly cordate, smooth- ish, limited by an impressed line; surface smooth or irregularly wrinkled by growth lines; right valve with a wide hinge platform on which are placed three cardinal teeth and a socket for the anterior left lateral ; the nymph is limited above by a deep groove.
Length, 87 mm.; height, 73 mm.; diameter, 53 mm.; type.
Length, 67 mm.; height, 61 mm.; diameter, 47 mm.
Remarks.—From the Aphrodina pacifica, this species is dis- tinguished by its deeply excavated area of the escutcheon and greater convexity of its valves. The hinge is preserved in a specimen of the right valve, but its details are obscured by grains of matrix. Its structure is essentially similar to that of Aphro- dina pacifica except that it is heavier and the posterior nymph is much stronger. The posterior right cardinal appears to have been bifid. The escutcheon is well marked and clearly differen- tiated by a deeply impressed line. Possibly related to this spe-
58 BULLETIN 111 216
cies is Venus subsulcata Philippi? from Algarrobo, Chile. Callista pseudoplana Yabe and Nagao*® from the Upper Cretaceous of Saghalin Island may also be related. Types.—Paleontological Research Institution, Nos. 4858, 4859. Occurrence.—Baculites zone.
Genus LEGUMEN Conrad
Legumen peruvianum, n. sp. Plate 6, fig. 12 Shell thin, compressed or slightly convex, similar in form and sculpture to Legumen planulatum Conrad but is proportionally shorter and higher ; posterior side is well rounded and about twice as long as the more narrowly rounded, anterior side; umbos very low and compressed; the external surface is marked with close- set, concentric lines, stronger and more irregular on the anterior- ventral subzone, smoother and more irregular on the posterior side; a smoothish ray, extending from the umbo to the posterior- ventral margin, is sometimes evident; ventral margins generally broadly flexed in the middle; interior and hinge not known.
Length, 47 mm. (approximate) ; height, 21.5 mm.
Although this species is quite common at Tortuga, our speci- mens are fragmentary or merely surface impressions. The spe- cies 1s closely related to Legumen planulatum Conrad,2* the geno- type, the Peruvian form being shorter, higher and with a more expanded posterior side.
Type.—Paleontological Research Institution, No, 4846.
Occurrence.—Tortuga, lower and middle zones.
Genus ICANOTIA Stoliczka
Icanotia pacifica, n. sp. Plate 2 fig. 8
Shell elongate, soleniform, shghtly convex, rather thin; dorsal margin long, straight, the ventral margin parallel to it except near
255 elouillijoyoy, 18, AN iQrgelltlias ove Typ ates th
26
Die Tert. and Quart. Versteincrungen Chiles, 1887,
T abe : Naoao. Ween Nein tar Ts Yabe, H., and Nagao, T.: New o7 little-known
from North Saghalin (Lamellibranchiata and Gastropoda), Science Reports of the Tohoku Imperial University, 2d series, vol. 7, No. 4, 1925, p. 120 pl. 29, figs. 1, 1a, 1b, le. a Nee Wade, Bruce: The fauna of the Ripley formation on Coon Creek Tennessee, U. S. Geol. Survey, Prof. Paper No. 137, 1926 pp 90-91, pl. 29, figs. 1. ly ee "Ee
Cretaceous fossils
ltrs CRETACEOUS OF PaITA: OLSSON 59
the anterior end where it is smoothly curved; umbo and beak not differentiated ; surface is sculptured with radiating riblets or lines which are fine over the greater part of the shell surface but be- come coarse on the posterior-dorsal portion; hinge and interior not exposed.
Length, 76 mm ; height, 21 mm.; semidiameter, 4 mm.
Our single specimen is very fragmentary but it agrees closely in general characters with /canotia impar Zittel,** the genotype from the Gosau Cretaceous of Europe. J/canotia elicita Stoliczka?® from the Ariyalur group of India is wider posteriorly.
Type.—Paleontological. Research Institution, No. 4820.
Occurrence.—Baculites zone.
Superfamily MACTRACEA Family MACTRIDZ
Genus MULINOIDES, new genus Genotype.—Mulinoides chilca, n. sp.
The following is a description of the genus Mulinoides:
The shell is solid, strongly convex and with a well-differenti- ated posterior-dorsal area; hinge has strong, lateral teeth and a wholly internal ligament and resiliary pit; the hinge of the right valve has a deep resiliary pit which is placed immediately below
the beak and directed obliquely backwards, and it is bordered pos- teriorly by a narrow groove which separates it from the dorsal edge of the valve; the anterior side of the resiliary pit is lamellar which united with an upper arm forms an inverted V-shaped cardinal tooth; anterior and posterior lateral teeth are large, solid, bordered above by a groove in which the laterals of the opposite valve are received; a lunularlike area is present, marked off by a line or groove and by a change in sculpture.
Remarks—The majority of the Cretaceous Mactride have been referred by authors to the genus Cymbophora Gabb, based cn AMactra ashburnerti Gabb of the Californian Cretaceous. The hinge of the genotype has been figured by Packard®° and by
28 Zittel, K. A. von: Die Bivalven der Gosaugebilde, Denksehr. Akad. Wiss. Wien, vol. 25, 1865-66, p. 120, pl. 2, fig. 4; same figure in Dall, Zittel Text-book of Paleontology, 1913, fig. 814.
29 Stoliczka, F.: Cretaceous fauna of southern India. The Peleeypoda, Mem. Geol. Surv. India, vol. 3, 1871, p. 168, pl. 4, fig. 16.
80 Packard, HE. L.: Mesozoic and Cenozoic Mactrine of the Pacific
Coast of North America, Bull. Dept. of Geol., Univ. Calif., vol. 9, No. 16, 1916, p. 298, pl. 26, figs. 4, 5,
60 BuLuLeETIN 111 218
Stephenson*! for several other species from the Coastal Plain of the United States. As noted by Stewart,” the Mactra araucana d’Orb.** fromm the Cretaceous of Quiriquina is probably a member of this genus. Dall®* considered Cymbophora merely a subgenus of Spisula, stating that it differed chiefly from the typical genus by the elevated edges of the chondrophore pit and by a posterior slit or sinus above it. Stephenson elevated Cymbophora to the rank of a genus, and this procedure was followed by Stewart. Our specimens from the Upper Breccia zone have the valve cavity filled with a cemented matrix so that it has not been pos- sible to clean or uncover the hinge structures thoroughly. — Its main features, however, are determinable. The hinge is solid with strong, enlarged lateral teeth and in these characters it resembles many species of Mulinia. The edges of the resiliary pit or chondrophore are prominent, lamellarlike and a deep groove or slit borders the posterior side. Whether the resiliary pit forms a more or less, independent, spoon-shaped structure as figured by Packard for Cymbophora ashburnerti cannot be determined but in Mulinia as well as in other Mactras, the edges of the resiliary pit are often thin, raised and free. The typical species of Cymbophora are shown as having, narrow, lamellarlike laterals and the form of the shell is trigonal and often elongated as common to many Spisulas. The slit or groove, which borders the posterior side of the pit or the adjacent under surface of the dorsal edge of the valve probably served for the attachment of the ligament. Although the Peruvian species agrees in its hinge structure with that described or figured for Cymbophora, there are obvious differences which seem important. These characters are the more
21 Stephenson, L. W.: North Carolina Geol. Econ. Sur., vol. 0, pt. 1 ISB), 1D) c
ae AG 335-339. 32
Deeclale 38 Wilekens, O.: Revision der Fauna der Quiriquina-Schichten, N. Jahrb. f. ete. BB., vol. 18, 1904, pp. 251-260, pl. 20, figs. 5-7.
34 Dall, W. H.: Trans, Wagner Free Institute of Science, vol. 3, pt. 4, 1898, p. 879.
Stewart, R. B.: Acad. Nat. Sci. Philadelphia, Spec. Pub. No.3, 1930,
219 CRETACEOUS OF PAITA: OLSSON 61
sclid, rounded or convex shell, stronger, less lamellar, lateral teeth and a resiliary pit which is more typically mactroid in form. The posterior-dorsal area is well marked and, as in Mulinia, 1s limited from the rest of the surface by an angled ridge. A large, lunular area is present, covering the whole of the anterior side and it is marked off by a groove and a change in sculpture. This genus is represented by two species in the Peruvian Cretaceous. Mulinoides chilca, n. sp. Plate 7, figs. 4, 7-9
Shell of medium size, solid, subovate to subtrigonal in torm and strongly convex; sculpture is formed by concentric riblets which are strongest on the central portion and on the anterior side, with the beaks and umbonal portions generally smoother ; a wide, flattened, posterior-dorsal area is present and defined by a keel or angular line extending from the umbo to the posterior, basal angle of the valve; the anterior side has a large lunular area, defined by a grooved line extending from the beak to the anterior, basal corner at which line, there is a change in sculp- ture, the concentric riblets becoming much coarser, since only the alternate ones are retained; hinge as described above; inter- ior filled with matrix.
Length, 51 mm.; height, 45 mm.; semidiameter, 21 mm.
Types.—Paleontological Research Institution, Nos. 4854, 4855, 4856.
Occurrence.—Baculites zone,
Mulinoides chicama, n. sp. Plate 6, fig. 7 Shell small, subtriangular, the umbos nearly central; valves
subequilateral, the anterior and posterior dorsal margins almost straight or weakly arched and meet above the beaks to form an approximate right angle; the valves are strongly convex, the maximum inflation situated near the middle of the disk; a well- marked umbonal angle extends from the beak to the posterior- ventral margin, above it the dorsal area is wide but set off from the rest of the surface by its stronger sculpture; surface is smooth in the middle and on the umbos but with strong, regular, con- centric riblets in the central portion and on the lunular and
62 BULLETIN 111 220
posterior-dorsal areas; hinge and interior not exposed. Length, 22 mm.; height, 18.5 mm.; diameter, 13.25 mm. Agreeing generally with Mulinoides chilca in form but much smaller. Type.—Paleontological Research Institution, No. 4852. Occurrence.—Tortuga, lower fossil bed.
Superfamily TELLINACEA
Family DONACIDZE Genus MACRODONAX, new genus
Genotype.—Macrodonax peruviand, i. sp.
The following is a description of the genus Macrodonax:
Shell large, solid, donaciform, the posterior side longer than the anterior and sharply truncated marginally; sculpture is dis- crepant on the two sides, the posterior portion being strongly ribbed, nodose, while that of the anterior portion is concentric ; ligamert external; the hinge is strong but known only from the right valve which has the following characters :—hinge plate stout with two cardinal teeth,—the posterior one being heavier, and two. strong lateral teeth placed distantly; sockets for the insertion of the laterals of the opposite valves border the superior side of the right laterals; valve margins plain; pallial sinus not known.
Macrodonax peruviana, n. sp. Plate 1, figs. 3, 4
Shell large, solid with a Donax or Chion-like form; valves only moderately convex, appearing externally as if somewhat flattened ; the beak is very small, touching the hinge line and lying just above the angle between the cardinal teeth; anterior side is somewhat longer than the posterior and both are narrowly rounded at the ends; the posterior side has a sharply flattened ov truncated submargin; the surface sculpture is divided between tsvo areas, that of the posterior side which consists of small and large radial riblets decussated by concentric lines, and that of the anterior side ornamented with coarse, more or less waved, con- centric ridges only ; there are three or more rows of large, double-
22 CRETACEOUS OF. PAITA: OLSSON 63
based spines as indicated in the figures ; characters of interior and pallial line not known, Length, 118 mm. ; height, 72 mm. ; semidiameter, 21 mm. Type.—Paleontological Research Institution, No. 481t. Occurrence.—Baculites zone.
Family TELLINIDZ Genus TELLIDORA (Moérch) H. and A. Adams Subgenus TELLIPIURA, new subgenus Genotype.—Tellidora (Tellipiura) peruana, n. sp.
The following is a description of the subgenus Tellipiura:
Generally similar to Tellidora in form and in possessing strong- ly dentated, dorsal margins but differs in being equivalved and in having a sculpture of strong, closely spaced, concentric riblets.
Tellidora (Tellipiura) peruana, n. sp. Plate 6, figs. 13-16
Shell of medium size, equivalve, subtrigonal to subrounded in outlines, the length being slightly greater than the height; the valves appear to be nearly flat but in reality are slightly convex as may be seen when viewed from above; the hinge margins, particularly on the posterior side is strongly dentated by a series of sharp, toothlike projections similar to those found on Recent species of Tellidova; the beaks are small, sharply pointed and curved forward, there being no clearly differentiated umbos; the sculpture is formed by a series of regularly spaced, concentric riblets which are persistent over the whole shell and overrun by finer concentric threads; most examples of the right valve show a weakly differentiated posterior-dorsal area either by a smooth- ing of the sculpture or by a faint furrow; in the left valve this area is slightly flexed.
Beneth, 25.5 mm, s.height, 22 mand. diameter, = -\= - :
Length, 21.5 mm.; height, 22.5 mm.; diameter, 4.5 mm.
ieneth, 26 mma, ; height, 19,5 mam.; diameter - --- .
A rather poor impression of the hinge of the left valve shows the dentition and the immersed ligament to be essentially similar to that of Tellidora burneti Broderip and Sowerby of the West
64 BULLETIN 111 222
Coast Recent. The latter it also resembles closely by its shape, toothed dorsal margins and the slight but distinct — posterior- dorsal flexure.
The Asterte-like form and strong sculpture is also similar to that of dstartemya Stephenson*®, recently described from the Navarro group of Texas but differs in shape and by its toothed margins.
Types.—Paleontological Research Institution, Nos. 4847, 4848, 4849.
Occurrence.—Lower fossil zone, Tortuga.
Superfamily SAXICAVACEA Family SAXICAVIDAE Genus PANOPE Menard
Panope frailia, n. sp. Plate 4, fig. 9
The shell is medium-sized, broadly subelongate, equivalve, convex and its texture rather thin; umbos wide, placed at the anterior one third with the maximum inflation a little above the middle; ventral margin straight in the middle zone, becomin® roundly curved towards the ends; dorsal and ventral margins not quite parallel, the dorsal side sloping somewhat towards the pos- terior end which appears somewhat produced and bluntly point- ed; shell widely gaping at both ends; surface smooth except for growth lines which are sometimes crowded together forming irregular wavelike undulations ; internal characters not known.
Length, 98 mm.; height, 48.5 mm.; diameter, 33 mm
The unique specimen is not well preserved, having lost the greater part of the umbonal portion. The subelongated form re- calls that of Panope goldfussi (Wagner) of the Floridian and lower Chesapeake Miocene. Panope simplex Htipe from the QOuiriquina beds has a similar form but the beaks are more cen- tral.
6 a] . . ~ 5 ~ 85 Stephenson, E. W.: The larger invertebrate fossils of the Navarro
group of Teaas, The University of Texas Pub., No. 4101, 1941, pp. 173, figs. 1-3.
ups CRETACEOUS OF PaitTa: OLSSON ef)
Type.—Paleontological Research Institution, No. 48309. Occurrence.—Baculites zone.
Superfamily MYACEA
Family CORBULIDAE Genus CORBULA Lamarck
Corbula tuma, n. sp. Plate 6, figs. 8-11
Shell of average size, strongly convex, with a subovate outline, sharply constricted in the posterior region and produced to form a long, narrow snout at the end; the left valve is only slightly smaller than the right, partly embraced by it and with ap- proximately the same degree of convexity ; umbos wide, full with the beaks nearly central; the sculpture is formed by close-set, concentric lines, a trifle weaker in the left valve; hinge and in- terior not seen.
Length, 10.5 mm. ; height, 6.25 mm.; diameter, 6.5 mm. (type).
This species will be recognized by its generally small size, form and long, beaklike posterior end, It is common in the lower and middle fossil bed at Tortuga.
Types.—Paleontological Research Institution, Nos, 4841, 4842, 4843, 4844.
Occurrence.—Tortuga. Corbula broggii, n. sp. Plate 6, figs. 1-3
The shell is large for the genus with nearly equal and similar valves and of a subelliptical form; the left valve is somewhat smaller than the right but otherwise very similar in form and sculpture; umbonal area wide, passing upward into the small, adjacent beaks which are placed a little back or posterior of the middle line; the anterior side is longer, broadly rounded at the end, the posterior side shorter, narrower and somewhat pointed at the end; posterior-dorsal area well defined, somewhat smaller in the left valve and bordered by a rib or small keel; surface sculptured with coarse, closely spaced concentric riblets ; interior and hinge not known.
Length, 31.5 mm.; height, 20.5 mm.; diameter, 13 mm. (type).
66 BuLuerin 111 224
Length, 38 mm.; height, 25 mm.; diameter, 16 mm,
Perhaps to be referred to Carycorbula, this species differs from most other Corbulas by its unusually large size. Three specimens are known.
Type.—Paleontological Research Institution, No. 4540.
Occurrence.—Baculites zone.
Class GASTROPODA
Subclass STREPTONEURA Order ASPIDOBRANCHIA Suborder DOCOGLOSSA Superfamily TROCHACEA Family TROCHIDA® Genus TECTUS Montfort Tectus tschudi, n. sp. Platesoseneaso
The shell is rather solid with a high, conic form and a sculp- ture formed by two rows of individual nodes, the smaller or in- ferior row placed closer to the suture than the superior is to the upper suture; base flattened to somewhat impressed, smooth; no umbilicus.
Height, 18.5 mm. (imperfect) ; diameter, 19 mm.
Only one specimen is known of this interesting species. It is named for Dr. J. J. von Tschudi, who as a naturalist travelled ex- tensively in Peru between the years 1838 and 1842.
Type.—Paleontological Research Institution, No. 4874.
Occurrence.—Baculites zone.
Superfamily SUBULITACEA
Family PSEUDOMELANIIDZE Genus PSEUDOMELANIA Pictet and Campiche Pseudomelania simplex, n. sp. Plate 12, fig. 17
Length of shell about 18 mm., with a high spire of flat-sided whorls and a smooth surface; suture lines distinct; last whorl with a sloping base; aperture incomplete in type specimen, the columellar area appearing to be excavated and with a thin ridge of callus on the parietal wall.
Length, 18 mm.; diameter, 6.75 mm.
A small, plain shell with a fairly long spire of about seven,
225 CRETACEOUS OF ParTa: OLSSON 67
flat-sided whorls preserved on the type. Lacking any distinctive characters, the present assignment of this species to Pseuc’omelan- 1a is provisional,
a
Type.—Paleontological Research Institution, No. 4872
Po
Occurrence.—Tortuga, lower fossil bed.
Superfamily NERITACEA
Family NERITIDZ Genus NERITA Linné Nerita jayanca, n. sp. Plate 9, figs. 6, 7
Shell small, subglobose or ovate with a very small, low spire and large, convex, embracing body whorl; whorls about three, the suture quite distinct; aperture crescentic; outer lip with an inner, marginal border, slightly more thickened within and bord- ered by a zone of small pustules; inner lip straight, the columellar area large, flattened, its edge bordered by four or five small teeth ; surface smooth or marked with lines of growth which near the lip may be grouped in narrow bands.
Height, 8 mm.; diameter, 9 mm. (holotype).
Height, 11 mm.; diameter, 12 mm.
This species resembles Nerita wmzambiensis Woods** from the Cretaceous of Pondoland but is smaller and has a less ex- panded body whorl and somewhat higher spire.
Types.—Paleontological Research Institution, Nos. 4875, 4876.
Occurrence.—Tortuga, lower fossil bed.
Order CTENOBRANCHIATA Suborder T/ENIOGLOSSA
Superfamily RISSOACEA Family MICROMELANIIDZE Genus STALIOA Brusina Stalioa agnia, n. sp. Plate 12, figs. 5, 15, 16
Shell very small, rissoid, with a medium length, conic spire;
36 Woods, H.: The Cretaceous fauna of Pondoland, Annals of the South African Museum, vol. 4, No. 12, 1906, p. 311, pl. 37, figs. 14, 15.
68 BuLuLEetTIn 111 226
body whorl about two-thirds of the total length ; base imperforate or with a small chink present in some cases; surface smooth ; sutures distinct, generally with a bordering band; aperture semi- lunate, with a continuous peristome; outer lip heavily thickened, strongly impressed on the back.
Length, 3 mm.; diameter, 1.8 mm. (type).
The measurements given above are of the holotype but most of the specimens are much smaller. A narrow cord borders the low- er side of the suture in most specimens and the body whorl im- mediately behind the heavily thickened lip is generally deeply impressed, The general contours of this shell and its thickened lip are similar to Stalioa Deschiensi (Deshayes)**, an Eocene species from the Paris Basin,
Types.—Paleontological Research Institution, Nos. 4877, 4878.
Occurrence.—Tortuga, upper zone.
Superfamily CERITHIACEA Family TURRITELLID Genus MESALIA Gray Mesalia janja, n. sp. Plate 10, figs. 1-3 Shell of medium size with the rapid taper common to most species of the genus; whorls convex and in the adult stage with two strong, spiral keels; nucleus is not known; the earliest spire whorls preserved on our specimens are unicarinate or provided with a single, large, revolving keel placed just below the middle ; a smaller spiral is introduced on the sloping shoulder above and which increases rapidly in size and soon becomes nearly equal in strength to that of the lower or primary spiral keel; the main whorls are double keeled and the spiral interspaces are practically smooth; on the body whorl, a third keel less strong than the other two borders the base; growth lines have a deep sinal in- flexion in the middle and in the adult become coarse and crowd- ed on the back of the last whorl. Length, incomplete 25.50 mm.; diameter, 13 mm.
37 Cossmann, M. and Pissarro, G.: Iconographie complete des Coquilles Fossiles de |’Eocene des environs de Paris, 1910-1913, pl. 14, figs. 90-2.
227 CRETACEOUS OF PAITA: OLSSON 69
Length, incomplete 25 mm.; diameter, 11.75 mm.
This beautiful species is plentiful at Tortuga and in the am- monite beds at La Mesa. It resembles closely the figures of the Persian Cretaceous forms referred by Douville** to Mesalia fasci- ata Lamarck, Mesalia fasciata is a Calcaire Grossier species of the Paris Basin and the figures given by Cossmann and Pissarro*® do not resemble closely either the Persian or Peruvian fossils. Specimens of Mesalia fasciata from Grignon, France are in the Harris collection at the Paleontological Research Institution. These specimens are similar to the figures commonly published for this species in having a sculpture formed of three or more spiral cords. The earliest spire whorls of Mesalia fasciata are smooth, flat-sided, their lower edge somewhat angled or keeled over the suture. This smooth stage includes eight or more whorls. The lower angle of the whorl later forms the first spiral but it is soon followed by a second spiral between it and the upper suture. In the bicarinate forms of Mesalia fasciata these two primary spirals may continue to form the dominant sculpture of the main whorls but the commonest types have three or more spiral cords of nearly equal strength. In Mesalia janja the early postnuclear whorls are more strongly keeled at a much earlier stage than in Mesalia fasciata indicating that the two species are not closely related.
Types.—Paleontological Research Institution, Nos. 4879, 4880, 4881.
Occurrence—La Mesa. Tortuga beds, lower horizon,
Genus WOODSALIA Olsson Woodsalia paitana, n. sp. Plate 11, fig. 5
Shell is of medium size, robust, composed of relatively few and fairly rapidly tapering spire whorls; nucleus and earlier whorl
38 Douville, H.: Mission Scientifique en Perse par J. de Morgan, tome troisieme, Etudes Geologiques, pt. 4, Paleontologie. 1904, pp. 329, 330, pl. 47, figs. 23-27.
39 Cossmann, M. and Pissarro, G.: Iconographie complete des Coquilles Fossiles de l’Eocene des environs de Paris, 1910-13, pl. 21, figs. 126-9.
70 BULLETIN 111 228
of spire not known; the first whorls preserved on our spec- imens have two subequal spiral cords situated just above the lower suture; on the following whorls, the upper spiral enlarges more rapidly than the other and becomes a sharp, narrow keel while the lower spiral is much less pronounced; area above the keel is concave and smooth; base of last whorl convex but sculpture details not known; growth lines, as in I!’oodsalia, have a wide, inward curve or sinus which lies along the peripheral keel. Length, 47 mm. (spire incomplete) ; diameter, 24 mm. Type.—Paleontological Research Institution, No. 4882. Occurrence.—-Tortuga, lower fossil bed.
Wocdsalia paitana robusta, n. subsp. Plate 11, figs. 3, 9
The shell is wider and of more conic form with the periphery of the whorls sharply edged or keeled and the lower spiral is nearly absent ; surface of whorl above peripheral keel is flat, slop- ing and smooth; growth lines with a wide sinus in the peripheral zone.
This form is possibly a distinct species but our material is not decisive in this respect. From |Voodsalia negritensis Woods of the Eocene Negritos beds, these Cretaceous species differ most strongly in having the upper spiral cord enlarging and forming the peripheral keel while in the Eocene species, it is the lower cord that enlarges to form the periphery of the mature whorls.
Types.—Paleontological Research Institution, Nos. 4883, 4899.
Occurrence.—Tortuga, lower fossil bed.
Genus TURRITELLA Lamarck, sensu lato Turritella lama, n. sp. Plate 10, figs. 5, 8, 10
Shell of medium size; spire slender in youth, later increasing more rapidly in diameter; sutures linear but with a concave su- tural zone so that the profile of the whorl appears more or less convex; nucleus and apical whorls not known but the earliest spire whorls preserved in any of our specimens, have three, pri- mary, revolving spirals, equally separated from each other and from the sutures ; smaller spiral threads appear in the interspaces ;
229 CRETACEOUS OF PArTa: OLSSON (ial
the three, primary spirals decrease steadily in size and in the adult are no stronger than the others; in the adult, the lower edge of the whorl which overhangs the base, has generally stronger spi- rals; pattern of growth lines like those of saposa.
Length, 23.5 mm.; diameter, 10 mm.
Length, 24.5 mm. ; diameter, 8.75 mm.
Length, 20 mm.; diameter, 8 mm.
Length, 18.25 mm.; diameter, 8.15 mm.
Estimated length of average specimen when perfect about 35 mm.
From Turritella saposa with which this Species, OCeuTS, 1h 1s distinguished by its more rapid taper, wider, more convex whorls and finer sculpture in the adult stage.
Type.—Paleontological Research Institution, No. 4884; other specimens, Nos. 4885; 4886.
Occurrence.— Tortuga, lower zone.
Turritella saposa, n. sp, Plate Oy fess 45709) aoe 112
Shell relatively small, with a slender, tapering spire; whorls humerous, appearing flat-sided or only slightly convex between linear and only slightly excavated sutures in the adult stage ; nucleus and apical whorls unknown but the earlier observed whorls have three primary, revolving cords or lire, equidistant from each other and from the lower suture; they are typically. firely nodulated by the growth lines, their interspaces smooth; a fourth, smaller, nodulated spiral borders the upper sutures; on the later turns, the spiral lire increase in numbers through the addition of new threads between the primaries and_ still finer spirals occur in their interspaces ; growth lines sinuous, with the axis of the inflexion placed just above the middle or at the poster- ior third.
Dimensions of figured specimens as follows:
Length, 20.5 mm.; diameter, 7.75 mm,
Length, 26.5 mm. ; diameter, 7.50 mm.
Length, 20.75 mm. ; diameter, 7 mm.
Length, 18.75 mm.; diameter, 8.75 mm,
Length, 21.5 mm.; diameter, 8 mm.
We Buuuetin 111 230
Type.—Paleontological Research Institution, No. 4887; other specimens, Nos. 4888-4891. Occurrence.—Tortuga, lower zone.
Turritella prechira, n. sp. Plate 10, fig. 13
Shell of medium size, slender; whorls 10 or more; nucleus and apical whorls unknown; the spire whorls have two strong, pri- mary spirals separated from each other by a concave band; sutures indistinct, bordered on the superior side by a small cord; on the last whorl, this sutural cord becomes enlarged and forms the periphery ; fine spiral threads occur in the space between the primaries on well-preserved specimens.
Length, 31 mm.; diameter, 8.5 mm.
This species resembles Turritella chira Olsson of the Saman sandstones and the Chira shales but the primaries are stronger and the form is more slender, It also resembles the Turritella soaresana Hartt*® from Maria Farinha of eastern Brazil. White’s figure shows three strong spirals although in his description only two are mentioned. Our specimens are wind eroded but the species can be easily distinguished by its slender form and strong sculpture.
Type.—Paleontological Research Institution, No. 4892.
Occurrence.—La Mesa.
Turritella ceiba, n. sp. Plate 11, figs. 6, 15
Shell large, solid, with a rapid taper; protoconch unknown; the earlier known whorls have a convex profile caused by two strong, primary cords which encircle the middle zone; on the following turns additional spirals appear above the two, primary ones ; half-grown shells have an irregular sculpture with one or more cordlike spirals around the lower quarter and smaller spirals above; when well preserved, very fine spiral threads cover the primary sculpture and impart to the surface, a coarse, clothlike texture; in large specimens the mature whorls are generally smooth but whether normal or due to erosion cannot be deter-
40 White, C. A.: Cretaceous invertebrate fossils from Brazil, Archivos do Museu Nacional, vol. 7, 1888, pp. 160-161, pl. 18, figs. 8, 9.
231 CRETACEOUS OF PAITA: OLSSON UB!
mined.
Length, 114 mm. (incomplete) ; diameter, 32.75 mm.
This is the largest Turritella in the Cretaceous of the Paita region. The earlier whorls of the spire are strongly bicarinated, later the sculpture becomes irregular and weaker,
Types —Paleontological Research Institution, Nos. 4893, 4894.
Occurrence.—Baculites zone.
Turritella inuya, n. sp. Plate 18, figs. 10, 11
Shell of medium size and rather stout; spire conic with a fairly rapid taper, the mature whorls appearing flat-sided or only slight- ly convex; nucleus not known; earlier spire whorls observed are strongly sculptured and have one, primary spiral keel placed just above the lower suture; a second spiral appears shortly at the upper third and rapidly increases in size and on the more ma- ture whorls nearly equals the lower spiral in strength; these two spirals give the sculpture of the mature whorls a_ bicarinate character ; small but coarse spirals cover the remaining surface ; the primary spirals, as well as the larger ones of the secondary series, are nodulated by the lines of growth; the periphery of the last whorl has a double keel and the flattened base below it, is covered with fine spirals.
Length, 32 mm. (imperfect) ; diameter, 14 mm.
Types.——Paleontological Research Institution, Nos. 4895, 4806.
Occurrence.—Tortuga, lower zone,
Turritella prelissoni, n. sp. Plater Gaatioie 2,
Shell of medium size with afairly rapidly tapering spire ; nucleus and earlier spire whorls are not known; the first spiral whorl preserved on the type has two strong spiral cords, the lower one is the heavier; there is a small thread between the two pri- maries and one thread borders each suture; on the following turns, the spirals increase in number and on the last turn there are about seven in all; with exception of the slightly larger peripheral cord the spirals are approximately equal in strength; finer spiral threads are present in the interspaces; the growth lines become rather coarse on the last whorl so as to resemble a ribbed sculpture.
Length, 44 mm. (imperfect) ; diameter, 21 mm.
74 BuLuETIN 111 232
The type specimen is imperfect and has four whorls preserved. Its shape and sculpture is similar to that of Turritella lissont Woods"! from the Negritos Eocene. In the Cretaceous species, the spire whorls have two, primary, spiral cords while in lissont there are generally three. On a former occasion, I referred Twrritella lissoni to the genus Il’oodsalia*? of which Turritella negritosensis Woods is the genotype but the species apparently belongs to a different group.
Type.—Paleontological Research Institution, No. 4904.
Occurrence.—Baculites zone.
Turritella desolata, n. sp. Plate 15, figs. 4, 5
Shell of moderate size, turrited with a regularly tapering spire and numerous whorls; nucleus and earlier spire whorls un- known, the following ones have a slightly convex form resulting from the strength of the spiral cords; sculpture is formed by three strong, spiral cords separated by fairly wide, grooved intervals ; base flattened to slightly rounded.
Length, 31.5 mm.; diameter, 13.25 mm. (41% whorls)
Length, 33 mm.; diameter, 11 mm. (5 whorls)
Although common, all our specimens are poorly preserved, worn or thickly encrusted with matrix. Nearly complete spec- imens have about to whorls and a length of 45 to 50 mm. and a diameter of about 13 mm. Fragments indicate, however, that the shell sometimes became much larger. There are several, described species of Cretaceous Turritellas having three or four strong, primary spirals but which differ generally from the Peruvian by their more strongly convex whorls. In view of the poor preser- vation of our material, a careful comparison from published fig- ures alone is impossible.
Types.— Paleontological Research Institution, Nos. 4900, 4901.
Occurrence.—Baculites zone.
11 Woods, H., in Bosworth, T. O.: Geology of the Tertiary and Quar- tenary periods in the north-west part of Peru, 1922, p. 79, pl. 8, figs. 4, 5.
12 Olsson, A. A.: Contributions to the Tertiary paleontology of north- ern Peru, Pt. Il, Upper Eocene Mollusca and Brachiopoda, Bull. Amer. Paleont., vol. 15, 1929, pp. 79, 80.
233 CRETACEOUS OF PAITA: OLSSON 75
Turritella bartsia, n. sp. Plate 15, fig. 9
Shell large, coarse; spire long, with a very gradual taper; in the type only the three last whorls are preserved; the whorls have a bipartite sculpture which is formed by a central ridgelike spiral dividing the surface of each whorl in two, nearly equal parts, each of which has a concave profile; in the upper zone, the sculpture is formed by a strong, keeled ridge or spiral bordering the lower side of the suture and three or more, weak spiral threads lying just above the middle ridge; in the lower zone, the surface is concave, smooth and bordered near the suture by a keeled spiral less strong than the one bordering the upper suture ; base of whorl is rounded, the peripheral side bordered by a double keeled spiral.
Length, 80 mm. (imperfect) ; diameter, 30 mm.
The strong, medial spiral, dividing the sculpture of each whorl into two, nearly equal parts, is the most striking feature of this unusual species. The single specimen was collected loose near Pan de Azucar, east of La Brea. Its stratigraphic derivation is not positively known. The whorls are filled with a coarse, gritty matrix, unlike the Middle Cretaceous rocks outcropping in the vicinity. These Cretaceous rocks, mostly limestones, are over- lain by massive, barren sandstones which either represent shore deposits of the lower Eocene or Negritos formation or they may belong to Upper Cretaceous rocks equivalent in age to the Monte Grande.
Type.—Paleontological Research Institution, No. 4902.
Occurrence.—Pan de Azucar,
Turritella parinensis, n. sp. Plated figs: Ae 22
Shell rather large, stout, the mature whorls with a_ strong, basal or peripheral keel and spire with a fairly rapid taper; earlier nuclear whorls are not known but the later ones have two spirals which are placed on the lower half; the lower or more anterior of these nuclear spirals increases more rapidly in size and develops into the strong, peripheral cord or keel of the later whorls while the upper spiral becomes obsolete and eventually
76 Buuuetin 111 234 |
disappears; the surface of the mature whorls is deeply concave and smooth; base flattened and ornamented with six scabrous cords, the upper three are much stronger than the anterior ones; growth lines and the shape of the outer lip strongly sinu- ous and as figured; our most perfect shell measures about 8o mm. in length and 25 mm. in diameter.
Length, 52 mm. (apex missing) ; diameter, 25 mm. (type).
This species is common and characteristic of the Parinas sand- stones occurring generally with Carolia (Parinomya) parinensis ~ Olsson, It differs by its smoother whorls from Turritella boswor- thi Woods of which it is obviously the descendant. The growth lines have typically a very deep sinus which lies almost in the middle of the whorl between the upper suture and the peripheral keel. A smaller, shallower sinus is generally developed on the edge of the base just below the keel.
Types.—Paleontological Research Institution, Nos. 4897, 4808.
Occurrence.—Parinas sandstones. Parinas Point (holotype) ; Cabo Blanco; Parinas outcrops south of Talara. (Eocene).
Genus SECHURITELLA, new genus Genotype.
Sechuritella terebracincta, n. sp. me!
The following is a description of the genus Sechuritella:
Shell turritelloid in form, with numerous whorls, each with a prominent, revolving cord or keel bordering the posterior edge; surface generally smooth at maturity; growth lines sinuous, strongly antecurrent, indicating an obliquely inclined outer lip; a deep, anal sinus in the posterior keel.
Remarks.—TVhis genus will be distinguished from Turritella by its solid, posterior keel and strongly antecurrent lines of growth. Specimens more perfect than those now available may show other distinguishing characters such as the possibility of an anterior sinus in the outer lip and an anterior canal. The genus is rep- resented by two Peruvian species: the genotype, terebracincta and chacapoya. In the latter, the spire whorls are spirally sculp-
CRETACEOUS OF ParTA: OLSSON ian
bo Go is
tured but the surface of the following whorls soon become smooth. Sechuritella terebracincta is an accelerated species and the spire whorls are smooth at an early stage and the posterior cord is early developed. In species of Turritella with a strong, posterior keel, such as the group of Turritella praecincta Conrad and Turritella dickersoni Woods, the keel is relatively thin, flangelike and sharp- edged while in Sechuritella, this structure is an enlarged cord which thickens and becomes more solid with growth, its upper surface being relatively wide, flat, sloping, its edge smoothly rounded while its lower surface is narrow and often grooved. The aperture was longer and more produced than in Turritella and may have possessed an anterior canal.
Sechuritella terebracincta, n. sp. Plater ites higss: dis Geel On lubed:
The shell is large and solid, each whorl with a massive cord- like keel near the upper suture and separated from it by a sloping shoulder, while the lower or anterior side of the keel is sharply limited, sometimes by a groove; the surface of the whorl is smooth except for irregularities in the lines of growth; body whorl is higher than wide with a sloping or nonflattened base ; growth lines antecurrent.
Measurements of the fragmentary examples in our collection give only an incomplete idea of the actual size of the species. The specimen illustrated by figure to on Plate 11 has a diameter of about 26 mm. The taper of the spire was very gradual so that the original length of this specimen was probably between go to 100 mm. Cross sections show that the columella was unarmed and the walls of the whorl chambers heavily thickened in a concentric fashion. The keel is often hollow.
Types.—Paleontological Research Institution, Nos. 4903 to 4907.
Occurrence.—Baculites zone.
Sechuritella chacapoya, n. sp. Plates lets sede dlic
Shell is large, solid, with a fairly rapidly tapering spire ; whorls numerous (about six are preserved on the holotype), wider than
78 BULLETIN 111 236
high; the majority of the whorls have a sharply carinated keel on the posterior side; nucleus is not known; the earlier whorls preserved on our specimens are spirally sculptured, the upper- most spiral scon enlarging to form the keel while the other spirals decrease in strength and the surface of the whorls becomes smooth; aperture and base not preserved in available material ; srowth line pattern, like that of Sechuwritella terebracincta, 1s strongly antecurrent.
Length of imperfect specimen, 54 mm.; diameter, 23.25 mm.
From Sechuritella terebracincta with which this species oc- curs, it is separated by its more rapidly tapering spire, sharper keel and spirally sculptured spire whorls.
Types.—Paleontological Research Institution, Nos. 4908, 4909.
Family MELANIIDZE Genus MELANATRIA Bowdich Melanatria medialis, n. sp. Plate 12, figs. 8, 11
Shell of medium size, stout, with a high spire of six or more whorls; the spire tip or nucleus is lost on the type specimen; whorls of the earlier portions of the spire appear to have been smooth or marked only with very fine lines visible with a lens; on the succeeding whorls there is a single row of spinelike tuber- cles on the posterior side of the suture; these tubercles number about six to a whorl; on the last whorl, there are two rows of spined tubercles, the lower row placed on the edge of the base or periphery of the whorl with its tubercles arranged alternately with those of the upper row; aperture incomplete, the inner lip with a spread of callus; basal part of shell is smooth.
Length, 28.5 mm. (imperfect) ; diameter, 16.25 mm. (holo- type).
This species resembles Melanatria dimorphica Woods* from the Negritos formation at Negritos and La Brea but differs by the smooth apical whorl and in its fewer, spinelike tubercles of the body whorl.
43 Woods, H.: In Bosworth, Geology of the Tertiary and Quaternary periods in the north-west part of Peru, 1922 Dp. 83, pl 9) fess lila ab:
“ey
237 CRETACEOUS OF ParITA: OLSSON 79 Type.—Paleontological Research Institution, No. 4910. Occurrence.—Tortuga, middle fossil bed.
Genus GLAUCONIA Giebel Glauconia cordalis, n. sp. Plate 15, fig. 13
Shell rather solid, in form like Turritella with a long spire formed of numerous whorls; apex and earlier whorls unknown, the later ones having a flat-sided profile and sculptured with two, very strong, spiral cords which are divided medially by a deep groove; these cords are rounded on the anterior or lower side, flaring and thin-edged on the upper side; a deep, spiral groove forms the lower edge of each spire whorl, the suture being con- cealed by the overlapping edge of the next whorl; last whorl rounded, the sculpture becoming less pronounced; growth lines slightly sinuous in the middle; aperture with a continuous peris- tome which becomes free-edged in the adult.
Length, 33.75 mm. (imperfect) ; diameter, 15.75 mm. Length, 27.25 mm.; diameter, 14 mm.
The reference of this fossil to Glawconia is provisional pending the discovery of more perfect specimens. The shell is very solid and the sculpture is formed by two strong, broad, spiral cords. The aperture appears to have been rounded with a continuous and free-edged peristome.
Type.—Paleontological Research Institution, No. 4918.
Oceurrence.—Baculites zone.
Family POTAMIDIDZ Genus TROCOTAULAX, new genus
Genotype.
Trocotaulax elegans, n. sp.
The following is a description of the genus Trocotaulax :
Shell small or medium-sized with a high spire and regularly enlarging whorls; sutural area excavated; sculpture of noded spirals on the upper surface and plain spirals only on the base; mouth round with a thickened, continuous and free-edged peris- tome; a small potamid sinus at the end of the columella.
Remarks.—In referring this genus to the Potamidide, I have been guided by its general resemblance to some species of Ceri-
80 BULLETIN 111 238
thidea and by its circular mouth bordered by a thickened and con- tinuous peristome which anteriorly is slightly reflexed to form a small siphonal sinus. The flattened basis is sculptured with plain spirals only, The sutural zone is deeply excavated which sives to each whorl a convex form.
Trocotaulax elegans, n. sp. Plate 13, figs. 6-8
Shell small with a lengthened spire composed of eight whorls plus the missing nucleus; sutures lie in a smooth, excavated band so that each whorl is convex in form, the suture itself is indis- tinct or shows only as a thin line; sculpture of each whorl is formed by three strone cords which are coarsely noded by ribs which extend across from the edge of each sutural band; these ribs number about 14 on an average specimen; base flattened to slight- ly convex, sculptured by two strong spiral cords in the outer zone and three smaller ones in the inner zone; aperture circular, edged by a thickened peristome; a small potamid sinus at the end of the columella.
Length, 14 mm.; diameter, 7 mm.
Length, 15 mm.; diameter, 7 mm.
Types.—Paleontological Research Institution, Nos. 4911, 4912, AQI3.
Occurrence.—Tortuga, middle fossil bed.
Genus THIANASSA, new genus
Genotype.
Thianassa ciconia, n. sp.
The following is a description of the genus Thianassa:
Shell small, nassoid with a high and broad spire; sculpture is formed by straight narrow ribs and smaller, finely wrinkled spir- als; ribs are more or less noded at their upper ends thus giving to each whorl a narrowly shouldered form; last whorl is high with a gently sloping base ending in a short but straight anterior canal provided with a small, slightly reflexed siphonal sinus.
These shells resemble somewhat Elimia H. and A, Adams but differ by their generally shorter form and in some other features.
For the present, the genus may be classed with the Potamididee.
Thianassa ciconia, n. sp. Plate 138, fig. 5
Shell small with a broad, stout spire composed of five or more
239 CRETACEOUS OF ParTA: OLSSON 81
whorls, the nucleus not included; early portion of the spire more rapidly enlarging than the latter; each whorl appears narrowly shouldered by the ends of the straight, narrow ribs which are more or less sharply noded at the ends adjacent to the upper su- ture; these ribs are almost in a direct line across each spire whorl, numbering about seven to each turn; finer, wrinkled spiral bands cover the ribs and the wider interspaces, the spiral adjacent to the upper suture being the largest; last whorl is rather high with a gently sloping base ending in a short, straight anterior canal ; inner lip with a thick coat of callus on the columella and parietal wall.
Length, 15.75 mm.; diameter, 8 mm.
This peculiar species is represented by several specimens in varying degrees of preservation. Two species may be present, some examples are longer and have more numerous ribs than the form here figured. The straight, narrow ribs and _ finely wrinkled or decussated spirals are characteristic of all the speci- mens.
Type.—Paleontological Research Institution, No. 4914.
Occurrence.—Tortuga, middle fossil bed.
Genus RHINOTAMIDES, new genus Genotype.—Rhinotamides rudis, n. sp.
The following is a description of the genus Rhinotamides :
Shell cerithid with an elongate-conic spire of numerous, flat- sided whorls and a hexagonal section formed at first by scarcely differentiated ribs; on the later whorls, these riblike angles be- come nodose and form into two rows of sharp tubercles ; one row, that bordering the upper suture is the stronger, the other en- circles the peripheral angle; base strongly flattened and sculp- tured with spirals; columella with a single fold.
Rhinotamides rudis, n. sp. Plate 13, figs. 9, 13
Shell of medium size, stout with nine or more spirally sculp- tured whorls; early portion of spire has a hexagonal section, the corners of which form low ribs at first scarcely discernible but later becoming more pronounced; the ends of these ribs develop
82 3ULLETIN 111 240
into rows of strong tubercles or spines; rest of surface has fine and more or less alternating beaded spirals; base flattened with three or more rows of beaded spirals ; aperture not known,
Leneth, 31 mm. (imperfect) ; diameter, 21 mm. (holotype).
Lencth, 27 mm.; diameter, 15.5 mm.
A perfect example of this interesting shell is not known, Re- mains of the outer lip suggest that of Tympanotonos Schumacher to which this genus seems most closely related. As may be seen from the figure, a sinus or channel was presented at the posterior end of the lip. The spire whorls have a hexagonal cross section, tlie angles of which become ribs and bear strong, spiniform tuber- cles on the mature whorls. Judging by associated fragments, the spines are very large and strong in old shells.
Types.—Paleontological Research Institution, Nos. 4915, 4916.
Occurrence.—Tortuga, middle and lower fossil beds.
Genus SYMPANOTOMUS, new genus
Genotype.
Sympanotomus muricatus, n. sp.
The following is a description of the genus Sympanotomus :
Shell cerithid with a long spire ornamented with two rows of pointed tubercles, the lower row stronger than the other; base flattened ; inner lip with a thick, calloused platform.
Sympanotomus muricatus, n. sp. Plate 13; figs 4
Shell of medium size with a medium length, pointed spire of 10 or more whorls; nucleus not known; the earlier spire whorls have two, equally noded, spiral cords, the nodes of which connect across the intervening groove in riblike manner; on the follow- ing whorls, the lower cord gains rapidly in strength and becomes large and sharply noded on the mature whorl while the upper cord remains small and only feebly noded; on the last whorl, the nodes of the spiral cord average about 12 in number; base flat- tened and spirally sculptured; aperture in all specimens is poor- ly preserved but has a callus growth which forms an appressed platform ; a potamid, anterior sinus is present.
Length, 30 mm.; height, 16.25 mm.
Type.—Paleontological Research Institution, No. 4917.
Occurrence.—Tortuga, middle fossil bed.
241 CRETACEOUS OF PaAITA: OLSSON 83
Genus PYRAZUS Montfort
Pyrazus peruvianus, n. sp. ~ Plate 13, fig. 12
Shell small or medium-sized, with a long, slender spire of eight or more whorls, the tip being broken away in all our specimens ; the whorls have a pentagonal section formed by five strong ribs; on the spire, the ribs are nearly in line, straight, but tend grad- ually to revolve towards the left as growth proceeds and on the later turns, the ribs are more widely separated and stronger in- dividually ; spirals overrun the whole surface and consist of two sizes, a primary set of strong, finely noded spirals, about five in number on the spire whorls and about eight on the body whorl, and very minute spiral threads between the larger ones visible enly with a lens; aperture rounded produced forward but the tip of the canal is broken in all our specimens.
Kencth, 27 mm. ; diamenter, 12.5 mm:
The genus Pyragus is based on Cerithium ebinius Bruguiere, a Recent species but several Upper Cretaceous and Eocene forms have been referred to it by Cossmann, Douville and other Euro- pean workers. Among described species, Pyrazus peruvianus may be compared with Pyrazus pentagonatus (Schlotheim) from the upper Eocene of Italy, good figures of which are given by Cossmann**, both species having the ribs in fives and arranged in nearly straight lines. Douville*® records Pyrazus pyramidatus Deshayes,*® which is an Eocene species in the Paris Basin (Cuisian), from the Maestrichtian of Persia.
Type.—Paleontological Research Institution, No. 4950.
Occurrence.—Tortuga.
Genus NODIFAUNUS, new genus
Genotype.—Nodifaunus nodosus, n. sp.
The following is a description of the genus Nodifaunus:
44 Cossmann, M.: Hssais de Paléoconchologie Comparée, vol. 7, 1906, p. 120 ples lO oso Oo eliO:
45 Douville, H. : Mission scientifique en Perse par J. de Morgan, vol. 3, Etudes Géologiques, pt. 4, Paléontologie, 1904, p. 306, pl. 42, figs. 5, 6.
46 Cossmann, M., and Pissarro, G.:I[conographie complete des Coquilles fossiles de l’Eocéne des environs de Paris, tome 2., 1910-1913, pl. 42, figs. 5, 6.
84 BuLuetTin 111 242
Shell solid, with numerous whorls and a high spire; the early whorls are smooth, flat-sided to slightly convex, later ones de- veloping a row of large knobs or ribs on the superior side; on the mature whorl, the base becomes rounded, sloping; growth lines straight or only slightly sinuous in the middle; anterior canal short with no distinct siphonal sinus; aperture semilunate, the parietal wall with a thick coat of callus.
Remarks.—To this group belong two characteristic species which are common in the fossil zones in the Lower Breccias at Tortuga. The spire whorls are smooth, resembling Faunus, but in the later stages are ornamented by a row of large, spinelike knobs or coarse ribs, most strongly developed just below the upper suture. In form, the shell resembles the figures given fer Pseudobellardia Cox, 1931 based on Faunus auriculatus Schlotheim from the upper Eocene, Ronca beds of northern Italy. Pseudobellardia has the spire whorls ribbed and a definite spiral sculpture.
Nodifaunus nodosus, n. sp. Plate 12, figs. 6, 7% 10} 12
Shell solid, melanoid of an average length of about 34 mm., the spire is long, formed for the most part of flat-sided, smooth whorls, the apical portion slender, the middle part wider or more inflated ; sutures linear, distinct ; the surface is smooth except for a row of strong spinelike nodes on the upper side of the penulti- mate and mature whorls; these nodes number about seven to the turn; last whorl rather high with a smooth, sloping or rounded base; aperture semilunar with the inner lip or parietal wall cov- ered by a thick coating of callus; lines of growth straight or slightly curved in the middle.
Length, 34 mm.; diameter, 15.5 mm.
T-ypes.—Paleontological Research Institution, Nos. 4920, 4921, 4922.
Occurrence.—Tortuga, lower and middle fossil zones.
47 Wenz, W.: Handbuch der Paldozoologie, Gastropoda, Teil, 3, 1939, p. 697, fig. 2008.
243 CRETACEOUS OF PaAITA: OLSSON 8d
Nedifaunus costatus, n. sp. Plate 12, figs. 9, 14
Shell solid, like Nodifaunus nodosus in general characters but with a more slender spire and the smooth stage confined to the earlier whorls; axial sculpture somewhat variable in strength and stage of development but in most specimens begins quite early and consists of coarse, riblike folds which do not quite reach the lower suture; on the type, the ribs number about eight on the last turn and are placed alternately with those of the adjacent whorl; last whorl rather high with a smooth, slightly convex, sloping base; aperture melanoid, a strong covering of callus on the par- ietal wall and a short canal without a siphonal sinus.
Length, 31 mm.; diameter, 14 mm.
The typical forms of these two species are very distinct but some intermediate specimens occur which are more difficult to classify. Nodifaunus nodosus is generally a larger and stouter shell, the smooth spire whorls noticeably wider and the axial nodes appear later and are more spinelike. The young shell has an angled periphery and a flattened base sculptured with feeble spirals. In Nodifaunus costatus, the form is more slender and the axial nodes are more riblike in appearance. The young- est shells seen have a sloping and smooth base.
Types.—Paleontological Research Institution, Nos. 4923, 4924.
Occurrence.—Tortuga, lower and middle fossil zones.
Genus GLORIOCLAVA, new genus Genotype.—Glorioclava inca, n. sp.
The following is a description of the genus Glorioclava:
Shell of medium size, solid, with a rather long, smooth spire; spire whorls eight or more (apex unknown), slightly convex in profile; surface smooth except for very faint spiral threads; parietal wall with a thick coating of callus; growth lines straight or showing only a slight inflexion in the middle.
Remarks.—The aperture and anterior canal are seldom well preserved amongst the fossil cerithids and the relation and clas- sification of many fossil groups are consequently doubtful. In form,
S6 BULLETIN 111 244
Glorioclava resembles Clavocerithium Cossmann** but the spire whorls are entirely smooth and judging by the shape of the growth lines, the outer lip was without a sinus. In these char- acters the Cretaceous shell differs from J/ddingsella Olsson*® as well as in size. The nucleus and earliest spire whorls are not preserved in our specimens but as far as can be determined the surface was smooth except for very minute spiral threads.
Glorioclava inca, n. sp. Plate 12, fig. 13
Shell of medium size, solid, with a rather longish spire of seven or more whorls (apex unknown) ; in profile, the spire whorls are slightly convex between well-marked sutures ; surface smooth ; inner lip with a thick callus on the parietal wall.
Length, 37 mm. (incomplete) ; diameter, 15.5 mm.
Type.—Paleontological Research Institution, No. 4925.
Occurrence.—Tortuga, middle zone.
Genus PREVICARYA, new genus Genotype.—Previcarya peruviana, new species
The following is a description of the genus Previcarya:
The shell is stout, with a pointed spire of numerous whorls; earlier whorls with three strong cords, the upper one being reg- ularly noded, the others smooth; on the later whorls, the nodes of the superior cord enlarge to form strong tubercles, the other cords remain smooth or become obsolete; base flattened and sculptured with strong spirals; aperture with a continuous peristome, the posterior end of the outer lip with a small sinal groove; columella with a small fold.
Remarks.—This genus resembles Vicarya d’Archiac and Haime*® (genotype Vicarya verneult d’ Archiac) but is smaller and has the posterior sinus reduced to a groove at the junction of the outer lip with the body whorl while in true l’icarya, the
48 Wenz, W.: Handbuch der Paliozoologie, Gastropoda, Teil 4, 1940, p. 762, Abb. 2208.
49° Olsson, A. A.: Contributions to the Tertiary paleontology of north- ern Peru, Pt. 2, Upper Eocene Mollusca and Brachiopoda, Bull. Amer. Pal- eont., vol. 15, No. 57, 1929, p. 81, pl. 4, figs. 1-4. (See also foreword to this paper. )
50° Wenz, W.: Handbuch der Paldozoologie, Band 6, Teil 6, 1940, p. 741 Abb. 2145.
245 CRETACEOUS OF PaITA: OLSSON 87
posterior sinus is placed in the middle of the lip and forms a deep inflexion in the lines of growth. The aperture of Vicarya is also calloused. The genus Previcarya appears to have representative species in the Cretaceous rocks in many parts of the world. The Cerithium hispidum Zekeli?! from the Cretaceous of Gosau to- gether with Cerithium (Fibula?) inauguratum Stoliczka®? may belong to it. These species were referred by Cossmann* to Cimolithium Cossmann with Cerithium belgicum d’Orbigny, a Cenomanian species as type. Cossmann’s figure of Cimolithium belgicum differs too greatly from Previcarya peruviana for the Peruvian species to belong to the same genus. Previcarya may also occur in eastern Brazil (Maria Farinha) from which White** has figured a fragmentary specimen as Nerine@a inauguratum Stoliczka. Previcarya peruviana, n, sp. PlateslZeficstelen2e3 Shell of medium size, stout, with a moderately long, nearly flat- sided and sharply conic spire; whorls numerous, 13 or more; nucleus unknown; the earlier whorls are sculptured with three strong cords, the upper cord being strongly and regularly noded, the other two are smooth with the lowest cord a little larger than the middle one; on the later whorls the simple nodes of the pos- terior cord increase in size to become coarse and rather widely spaced sharp tubercles which on the largest specimens number about nine to the turn; the other two cords which are smooth persist on the later whorls but remain small or become faint to subobsolete; in addition there is a fine, submicroscopic spiral lining over the whole surface; young shells have a_ strongly flattened base with a bordering carina; on more mature shells, the base becomes more rounded and sculptured with three or 51 Zekeli, F.: Die Gastropoden der Gosaugebilde, Kh. geol. Reichsan- Wien. Abh., Band 1, 1852, pp. 115, 116, pl. 24, figs. 1, 2.
52 Stoliezka, F.: Cretaceous faunas of southern India, Paleontologia Indica, Mem., 1865-70, p. 193, pl. 15, figs. 15, 19, 20.
53 Cossmann, M.: Essais de Paléoconchologie Comparée, vol. 7, 1906, Os Bile
54 White, C. A.: Cretaceous invertebrate fossils, Archivos do Museu Nacional, vol. 7, 1888, p. 141, pl. 13, fig. 9.
88 BULLETIN 111 246
more strong spirals; aperture, when perfect, has a continuous peristome with a strong posterior sinal groove at its upper end; the complete outer lip is not known; columella with a _ small, oblique fold.
Height, 35 mm.; diameter, 16.75 mm. type.
Height, 34.5 mm.; diameter, 16 mm.
A common and characteristic species in the middle zone at Tortuga.
Types.—Paleontological Research Institution, Nos. 4926, 4927, 4928.
Occurrence.—Middle zone at Tortuga.
Family CERITHIIDZ
Genus TORTUCERITHIUM, new genus Tortucerithium teatilis, n. sp.
Genotype. The following is a description of the genus Tortucerithium: Shell cerithid with a long, tapering spire of numerous whorls at first sculptured with narrow, foldlike ribs and spirals; on the later turns the ribs become stronger and on the last divide into two rows of stout tubercles; aperture not known.
Tortucerithium textilis, n. sp. Plate 13, figs. 1-3
Shell of medium size to large, with a long, tapering spire of eight or more whorls; the nucleus is unknown; the whorls of the spire have a flat profile and are separated by distinct but waved sutures and their sculpture consists of strong, close-set, foldlike ribs which number about 11, at first straight but later become oblique and overrun by fine spiral threads; the axial ribs on the later turns are strongly thickened and more widely separated and on the last turn are divided into two rows of sharp tubercles, the upper set bordering the suture and the other encircling the periphery ; base slightly convex and ornamented with fine spirals; aperture incomplete, with a coating of callus on the parietal wall.
Length, 49.5 mm. (imperfect) ; diameter, 25 mm.
This is the largest and commonest cerithid at Tortuga and will readily be recognized by its slender form and characteristic sculpture. I have found no described species to which it appears at all closely related.
247 CRETACEOUS OF PaITA: OLSSON 89
Types.—Paleontological Research Institution, Nos. 4931, 4632, 4933. Occurrence.—Tortuga, middle fossil bed.
Genus PARINANA, new genus Morgana magma Woods, Plate 15, fig. 14
Genotype.
The following is a description of the genus Parinana:
Shell with pupoid outline, rather solid; spire long, composed of numerous smooth whorls except the earlier ones which may be sculptured with ribs and spirals; aperture with a thickened, continuous peristome and a Clava-like anterior canal; outer lip appressed, thickened with only a shallow sinal inflexion in the lines of growth; the base sloping and sculptured with strong spirals.
Remarks.—In 1904, Douville** gave the name /rania to a group of species common in the Maestrichtian of Persia, the selected genotype being the Vicarya fusiformis Hislop. The type species also occurs at Rajamandii, India, in beds variously referred to the late Cretaceous and Eocene. It is a smooth shell with a very deep, narrow sinus in the outer lip. The name “/rania’ being preoccupied in birds, was changed to Morgana by Cossmann*® who classed the genus in the Melanopside. Wenz*" places Mor- gana with the Potamidide. Woods** in his study of the Bos- worthian collection described two species from Peru as Morgana magma and costata. Morgana costata was later selected by Olsson*® as the genotype of Hopkinsiana and because of its well- developed cerithid aperture and canal, referred the species to the Cerithiidze. Parinana magma is a common and characteristic fos-
55 Douville, H.: Mission Scientifique en Perse par P. de Morgan, Etudes Geologiques, pt. 4, Paleontologie, 1904, pp. 319-322, pl. 44, figs. 1-18.
56 Cossmann, M.: Paléoconch. comparée, vol. 8, 1909, p. 164, pl. 3, figs. 14, 15.
57 Wenz, W.: Handbuch der Paliéozoologie, 1940, pp. 741. 742, Abb. 2146.
58 Woods, H.: In Bosworth, Geology of the Tertiary and Quaternary periods in the north-west part of Peru, 1922, p. 82, pl. 9, figs. 5, 6.
59 Olsson, A. A.: Contributions to the Tertiary paleontology of north- ern Peru, Pt. 2, Upper Eocene Mollusca and Brachiopoda, Bull. Amer. Paleont., vol. 15, No. 57, 1929; p. 84, pl: 6, figs. 8, 10, 11.
90 BULLETIN 111 248
sil in the Parinas sandstones. As noted by Woods this species bears much resemblance to Morgana fusiformis but differs by its larger size and more importantly in having only a shallow sinus in the outer lip. The anterior canal, although seldom pre- served, has a long, somewhat recurved beak similar to that of Clava and other related cerithids. These characters show that the Peruvian magma cannot belong to the true genus Morgana. The Vicarya ? sappho White and Vicarya ¢ daphne White from Brazil may belong to this genus. Parinana americana, n. sp. Plate 12, fig. 4
Shell small, pupoid and rather solid; spire long with eight whorls preserved on type (apex is broken); the spire whorls are strongly sculptured with four spiral cords of which the two outer ones are the strongest; these cords are coarsely and regu- larly noded; on the last whorl, the spiral sculpture has become obsolete and the surface is nearly smooth; aperture ovate, the inner lip thickened, its edge generally free; growth lines indis- tinct on the type but appear weakly sinuous in the middle.
Beneths 15 mim, diameter ©.5 oii.
The type material of this small species comprises four speci- mens, none of which is perfect.
T ype.—Paleontological Research Institution, No. 4929.
Occurrence.—Tortuga, middle fossil bed.
Superfamily CALYPTRAZACEA Family CALYPTRAIDA
Genus CALYPTRAA Lamarck Calyptrza aperta Solander Plate 9, figs. 10-13 Calyptrea is typically a Tertiary and Recent genus but some authors, such as Stoliczka, have recorded species from several Cretaceous localities but most of these records are based on casts or otherwise questionable material. The Peruvian examples from the Cretaceous of Tortuga and the Baculites zone belong not only to typical Calyptrea but they are apparently specifically iden- tical with Calyptrea aperta Solander (sometimes known as C. tro- chiformis Lamarck) common in the Eocene of Europe and North America. The Claibornian forms of this species have recentlv
249 CRETACEOUS OF PAITA: OLSSON 91
been illustrated by Palmer.®° Internal molds of a Calyptrea from the Roca beds of the Argentine are mentioned by Von Thering®! under the name of C. cf. pileolus d’Orb. and were first referred to C. aperta Solander by Boehm.*°
In our collections, Calyptr@a aperta is abundant in the middle fossil bed at Tortuga and one specimen was also found in the Baculites zone. Representative examples are figured. As typi- cal of the genus, young shells are very variable in form and sculp- ture. The sutures are generally distinct (except on the apical portion) and the individual whorls vary from flat to moderately convex. Many shells have the sutural zone strongly shouldered or it may be flattened and depressed, thus accentuating the ap- parent convexity of the whorls. The older portion of the conch tends to become smooth but elsewhere the sculpture is formed by a series of close, irregular radial wrinkles and small, ventrally directed, scalloped frills or pustules. The specimen from the Baculites zone has a high, conic spire and several rows of oblique- ly ascending pustules.
For comparison with the Cretaceous forms, I have also figured a specimen from the Eocene Parinas sandstones of Keswick Hills east of Negritos.
Our shells measure as follows:
Height, 18.5 mm ; diameter, 34 mm. Tortuga.
Height, 22 mm.; diameter, 26 mm. Tortuga.
Height, 25.5 mm.; diameter, 37.5 mm. Tortuga.
Height, 34 mm.; diameter, 37 mm. Baculites zone.
Figured Specimens.—Paleontological Research Institution, Nos. 4934, 4935, 4930. Eocene specimens (Parinas ss.), No. 4937.
Occurrence.—Tortuga, middle zone. Baculites zone, Also at Monte Grande.
60 Palmer, K.: The Claibornian Scaphopoda, Gastropoda and dibranchi- ate Cephalopoda of the southern United States, Bull. Amer. Paleont., vol. ip Noso2, 1937, p: 145, pl. 16, figs. 1,2, 3, 5.
sD von Ihering, H.: Les Mollusques Fossiles du Tertiaire et du Crétacé Supérieur de 1’ Argentine, Anales del Museo Nacional de Buenos Aires, serie III, tomo 7,.1907, p. 28.
‘2 Boehm, J.: Zeitschr. Deut. Geol. Ges., 1903, p. 72.
92 BULLETIN 111
bo oO fom)
Superfamily STROMBACEA Family APORRHAIDZ
Genus ANCHURA Conrad
Anchura pacifica, n. sp. Plate 14, fig. 1
Shell of medium size, fusiform with a slender, turrited spire; four whorls are preserved on the type, the apical whorls being missing ; the body whorl is about half the length of the shell and is ornamented with a single, strong, knoblike rib situated near the left side; the sculpture is cancellated on the spire whorls and formed by nearly equal ribs and spirals, the intersection of which is slightly noded; the ribs have vanished on the last whorl (ex- cept for the single one placed near the left side), only the spiral sculpture remains which is formed by a series of few widely spaced stronger spirals and intermediate smaller ones; the spirals are more or less nodulated by the lines of growth; the outer lip has a long, narrow, spurlike form, the end of which has been broken away in the type; anterior canal straight; columella not exposed.
Length of specimen (tip of spire and canal missing), 31 mm.
Diameter of specimen (wing incomplete), 17.5 mm.
This is the only species of Anchura known from Peru. It is characterized by its cancellated spire whorls,
Type.—Paleontological Research Institution, No. 4943. © Occurrence.—Baculites zone. it Family STROMBIDZE
Genus TORGNELLUS, new genus
Torgnellus peruvianus, vn. sp.
Genotype.
The following is a description of the genus Torgnellus :
In form, the shell is like Pugnellus Conrad (genotype P. typi- cus Gabb=P. densatus Conrad) but more massive and the ex- ternal surface is smooth or without definite sculpture; sutures covered with callus except perhaps in extreme youth; young shells are fairly regularly fusiform with a pointed spire, a long, straight anterior canal and with an upward pointed hook at the posterior end of the outer lip; with maturity and senility, the shell becomes thick, massive and irregular, the outer lip developing
251 CRETACEOUS OF PAITA: OLSSON 933
a massive lobe ending posteriorly in a blunt spur; the anterior canal is broadly appressed and turns sharply towards the left; spire in the adult is merely a small knob, appressed on the ven- tral side; aperture in the middle is quite wide with parallel sides.
Torgnellus peruvianus, n. sp. Plate 14, figs. 7, 8
Pugnellus, sp., Olsson, 1934, The Cretaceous of the Amotape Region, Bull. Amer. Paleont., No. 69, p. 66, pl. 9, fig. 5 (young specimen).
Shell of adult large or medium-sized, solid, completely cov- ered with callus and with a thick, expanded outer lip; no ribbed sculpture is developed at any stage, the surface of the whorls being essentially smooth ; in the very young, the shell has a prom- inent spire and quite evenly convex whorls; in the succeeding stages, a cover of callus is spread over the whole surface and with age becomes very thickly developed in certain areas, par- ticularly on the outer, posterior surface of the winged lip; the spire is completely submerged by the callus and usually develops into a small, lateral compressed, hooklike snout simi- lar to that found at the posterior end of the outer lip; anterior beak turned sharply to the left.
Length, 46 mm.; greater diameter, 39 mm. (across lip) ; lesser diameter, 22.25 mm. (transverse to lip).
Torgnellus is clearly allied to Pugnellus but differs by its heav- ier shell, more thickly covered with callus, absence of a ribbed sculpture and more importantly in having the anterior canal bent sharply to the left in the adult. Young shells have the straight anterior canal of Pugnellus. An interesting species described by Gabb as Pugnellus tumidus occurs in the Cretaceous of the island ef Quiriquina, Chile and has been well figured by Wilckens.**
Stewart has referred this species, together with the Californ- ian P. hamulus Gabb to Conchothyra but true Conchothyra of the New Zealand Cretaceous has no anterior canal. Marwick®?
63 Wilekens, O.: Revision der Fauna der Quiriquina-Schichten, N. Jahrb. fur Min. ete. BB. vol. 18, 1904, p. 205, pl. 18, figs. 2a, 2b.
64 Stewart, R.: Gabb’s California fossil type gastropods, Proe. Aead. Nat. Sci. Philadelphia, vol. 78, 1926, p. 358.
65 Marwick, J.: The Wangaloan and associated molluscan faunas of
Kaitangata-Green Island subdivision, Geol. Sur. N. Zealand, Pal. Bull., IN@s: Ik, UPB iE jos Ose
94 BULLETIN 111 252
places Conchothyra among the Struthiolariide. Type.—Paleontological Research Institution, No. 4938. Occurrence.—Baculites zone.
Genus PERUSTROMBUS, new genus Genotype.—Perustrombus wheeleri, n. sp.
The following is a description of the genus Perustrombus:
Shell large, solid, thickened by a heavy deposit of callus; adult with the spire completely concealed, the area of the spire is flattened and bordered by a massive, circling keel of callus which extends from the posterior end of the outer lip and is most strong- ly developed on the dorsal surface; outer lip massive, straight and thickened by a wide band of callus clearly marked off from the rest of the surface; surface smooth; anterior canal long, straight.
Perustrombus wheeleri, n. sp. Plate 14, figs. 1-3
Shell of large size, solid; the spire is completely concealed in the adult, the area covering the spire being flattened and_ bor- dered by a high, massive keel of callus; body whorl subcylindri- cal in form, convex and smooth but there are faint indications of former ribs showing through the callus; a massive cord- like keel of callus is formed at the posterior end of the outer lip and on the dorsal side assumes a high, humplike form; outer lip straight, long and strongly thickened by a wide band of callus; aperture sublinear of uniform width throughout; anterior canal long, straight, the end broken in the type specimen.
Length (tip of anterior canal broken), 77 mm.; greater diam- eter (ventral side), 40 mm., (with hump) ; lesser diameter (trans- verse to aperture), 32.5 mm.
Two specimens of this interesting species are known, the large holotype measuring 77 mm. in length and a smaller, more frag- mentary specimen which if complete would be about 50 mm. in length. This second shell although so much smaller than the holotype has the same heavily thickened lip, humped shoulder and flattened concealed spire. The keel which is so strongly formed on the dorsal side continues as a low fold across the ven- tral side as well. The form of the shell is decidedly Cyprea- or
253 CRETACEOUS OF PaAITA: OLSSON 95
Gisortia-like best seen in the younger specimen which is strong- ly compressed dorsal-ventrally. Type.—Paleontological Research Institution, No. 4939. Occurrence.—Baculites zone.
Subgenus ORTHOSTROMBUS, new subgenus
Genotype.—Perustrombus (Orthostrombus) tortugensis, n. sp.
The following is a description of the genus Perustrombus:
Shell of medium size, solid, with a short, pointed spire; the spire whorls are ribbed in the early stages; the sculpture and su- tures later become covered with a continuous coat of callus; aper- ture is broadly linear with parallel walls, the outer lip strongly thickened by a band of callus, heaviest at the posterior end; an- terior canal straight.
Perustrombus (Orthostrombus) tortugensis, n. sp. Plate 14, figs. 5, 6
Shell of medium size, solid and completely covered with a callus of variable thickness; spire is short, pointed at the end, and composed roughly of six whorls; young specimens are not available but the holotype has a series of small, oblique rib- lets, showing faintly through its covering of callus; the upper side of the whorls are impressed; growth lines showing faintly through the coat of callus are sinuous, retractive above towards the su- ture as in Pugnellus; aperture is broadly linear, with the inner and outer lips parallel; outer lip is strongly thickened by a wide belt of callus, especially so at the posterior side; anterior canal broken in the specimens available but was apparently straight.
Length, 40 mm. (imperfect) ; diameter, 24 mm. (holotype).
Length, 41.5 mm. (imperfect) ; diameter, 26 mm.
This elegant shell is represented in our collections by two spe- cimens. The species will be easily recognized by its short, conic spire and callus which covers the entire shell, including the sutures in the adult. Short, obliquely set ribs are visible through the callus on the spire whorls. On the back of the body whorl, the growth lines are seen to be sinuous, strongly retrac- tive above towards the suture as in Pugnellus. The outer lip has a broad band of callus on the back as in Perustrombus wheeleri
bo oO rs
96 BULLETIN 111
which assumes its greatest thickness at the posterior end where it forms the side of the deep, anal channel. A knoblike growth of callus is found at the edge of the parietal wall. The anterior canal is broken in our specimens but it was apparently straight.
Pugnellus ° cypreformis Olsson from Monte Grande can now be referred to Orthostrombus. This species was originally based on two specimens. The holotype, which is larger and has an ex- posed spire, will carry the name cypreformis. It differs from the Tortuga species in being much larger. The second Monte Grande specimen, that illustrated by figure 4, plate 9 of our Amo- tape report, is perhaps a new species of Perustrombus but being poorly preserved is best left unnamed until better material. is found.
T ype.— Paleontological Research Institution, No, 4940.
Occurrence.—Tortuga, lower fossil bed.
Genus CALYPTRAPHORUS Conrad
Calyptraphorus hopkinsi Olsson Plate 15, figs. 8, 12
Calyptraphorus hopkinsi Olsson, 1934, The Cretaceous of the Amotape
Region, op. cit., p. 68, pl. 10, fig. 2.
As near as can be determined from available material, this spe- cies appears to be a true Calyptraphorus although as pointed out recently by Palmer,®® the exact systematic position of the few Cretaceous forms referred to this genus will remain doubtful un- til specimens with the anterior canal and outer lip perfectly pre- served are known. Even in case Calyptraphorus hopkinst should not prove to belong to the typical genus, it is most certainly its direct precursor. The specimens here figured are from the Baculites zone at Tortuga and although fragmentary, serve to supplement our knowledge of this species, first described from Monte Grande.
Young specimens or those deprived of their covering of callus have a Faunus-like shape, tapering spire and close, linear sutures. The earlier whorls of the spire are ribbed but this sculpture soon disappears and the surface becomes smooth. The ribbed stage
66 Palmer, K.: The Claibornian Scaphopoda, Gastropoda and dibranchi-
ate Cephalopoda of the southern United States, Bull. Amer. Paleont., vol.
7, 1937, p. 242.
255 CRETACEOUS OF PaITA: OLSSON 97
may cover about six whorls and the smooth stage about six turns or more. The anterior canal although broken in all our specimens was long and narrow.
Figured specimens.—Paleontological Research Institution,
Nos. 4941, 4942. Occurrence.—Baculites zone.
Superfamily NATICACEA Family NATICIDZ Genus AMPULLINA Lamarck, sensu lato
Ampullina breccia, n. sp. Plate 9, figs. 2-4
Shell large, thick, ovate, imperforate, the spire slightly less than half the total length; whorls 5+, (nucleus not preserved), those of the spire are slightly convex, that of the body whorl is well rounded to slightly angulated in the middle; sutures dis- tinct, the bordering area is not flattened so that the spire is not scalar in form; aperture ovate, the inner lip with a thick spread of callus on the parietal wall which extends down as a band into the anterior portion of the outer lip; surface smooth but where well preserved, shows faint spirals; growth lines are retractive, oblique to the axis of the shell about 20 degrees and have a slight, flexure in the middle.
Height, 57.5 mm.; diameter, 44.5 mm. (type).
This species closely resembles Stewart’s™ figure of Ampullina oviformis Gabb from the Chico Cretaceous of Tuscan Springs, California. As Stewart notes, this Californian species is at least subgenerically removed from typical mpullina. From the asso- ciated Ampullina tortuga, the present species is distinguished by its form, and convex, nonscalar, spire whorls. The holotype be- longs to the Baculites zone but smaller and otherwise identical forms occur in the lower zone at Tortuga.
Type.—Paleontological Research Institution, Nos. 4944, 4945, 4946.
Occurrence.—Baculites zone. Lower Tortuga zone.
67 Stewart, R. B.: Gabb’s California fossil type gastropods, Poe. Acad. Nat. Sci. Philadelphia, vol. 78, 1926, p. 333, pl. 21, fig. 10.
98 BULLETIN 111 256
Ampullina tortuga, n. sp. Plate 9, fig. 1
The shell is fairly large, thick, imperforate, ovate with a mod- erately elevated spire about half the total length; nucleus not known; whorls about six; in the small shells, the sutural area is simply rounded but with growth becomes narrowly flattened and the profile of the spire becomes shouldered; small shells have a narrow umbilicus which later becomes covered by the spreading callus; aperture holostomous, subovate in outline; inner lip with a thick spread of callus over the parietal wall; outer lip imperfect on our specimens but judging from the shape of the lines of crowth, was only slightly oblique in the adult; surface smooth except for the faint lines of growth.
Length, 56 mm., diameter, 47 mm.
Young shells have a narrow, well-formed umbilicus which is soon covered by the encroachment of the callus of the inner lip. Mature shells have a strongly shouldered spire profile and the body whorl is large and subovate in form.
Type.—Paleontological Research Institution, No. 4947.
Occurrence.—Tortuga, lower zone.
Ampullina cumara, n. sp. Plate 9, fig. 5
Shell of medium size, nonumbilicate, with a short spire and a large, convex body whorl; nucleus not preserved on our speci- mens ; spire formed of about six or more, convex whorls between well-marked sutures; body whorl inflated, its greatest convexity lying opposite the upper third of the aperture; general surface of the shell is smooth, polished, but showing faint impressions of the growth lines and often still weaker indications of minute, irregular spirals; aperture semilunar, the outer lip not well pre- served on any of our specimens, was somewhat oblique as indi- cated by the growth lines; inner lip with a spread of callus on the parietal wall; anterior end of the aperture with a short, re- flexed canal.
Length, 29.5 mm., diameter, 25 mm.
This species. of which we have four specimens, differs strik- ingly from the other forms by its shorter, smaller spire and pro-
257 CRETACEOUS OF PAITA: OLSSON 99
portionately larger body whorl. Its general shape is similar to that of Ampullina willemeti (Desh.),°* which is the genotype of Crommium, except that it has no umbilicus and the spread of callus is therefore wider. Type.—Paleontological Research Institution, No. 4948. Occurrence.—Tortuga, lower zone.
Superfamily BUCCINACEA Family GALEODID4 Genus RHOMBOPSIS Gardner Rhombopsis meridionalis, n. sp. Plate 15, figs. 1, 2
Shell of medium size, fusiform with a high spire and _ fair- ly long anterior canal, strongly sculptured with ribs and spirals; nucleus missing on available specimens, the spire whorls remain- ing on type numbering about 414; the body whorl is rather large with a rounded shoulder ornamented with about to ribs which fade out across the base and upwards towards the suture; su- tural zone impressed, concave; in addition to the ribs, the surface is elaborately sculptured with strong, alternating spiral threads ; aperture incompletely preserved in type but shows a long, twisted anterior canal ending in a small but distinct canal; growth lines sinuous.
Length, 25.5 mm.; diameter, 17.75 mm.
In essential characters, this species resembles the Rhombopsis orientalis and microstriatus Wade from the Ripley Cretaceous of Tennessee differing principally by its broader form and more strongly curved anterior canal. The western species figured by Meek are less similar. Rhombopsis was proposed by Gardner, 1916, as a substitute name for Neptunella Meek, 1876, preoccu- pied by Gray, 1853. The group Neptunella was used as a sub- genus of Pyrifusus Conrad by Meek with Fusus newberryi as the genotype.
Types.—Paleontological Research Institution, Nos. 4953, 4954-
Occurrence.—Tortuga, lower zone.
6s Cossmann, M., and Pissarro, G.: Iconographie complete des Coquilles ° fossiles de L’Eocene des environs de Paris, tome 2e, 1910-1913, pl. 11, 64-17.
69 Wade, Bruce: The fauna of the Ripley formation on Coon Creek, Tennessee, U. 8. Geol. Survey, Prof-paper, 137, 1926, p. 142.
100 BULLETIN 111 258
Family FASCIOLARIIDA Genus LATIRUS Montfort Latirus tribulus, n. sp. Plates ibs tics
Shell fusoid with a spire about equal to the aperture in length ; whorls shouldered and sculptured with strong, knobbed ribs which number about eight on the last whorl; above the shoulder, the face of the whorls is constricted and concave, its sculpture smoother ; the shoulder and the surface of the whorls are covered by a series of strong spirals evenly distributed and separated by wide intervals; two or three of these spirals cross the top of the ribs on the shoulder angle which they render somewhat nodose with 10 or more placed on the base and over the anterior canal ; aperture and columellar area imperfect and covered with matrix.
Length, 42 mm: (imperfect) ; diameter, 28 mm.
The type specimen is poorly preserved with the columella covered by matrix. The generic reference to Latirus is therefore provisional until better material permits more certain identifica- tion,
Type.—Paleontological Research Institution, No. 4940.
Occurrence.—Baculites zone.
Genus FASCIOLARIA Lamarck
Fasciolaria sechura, n. sp. Plate 15, figs. 3, 10
Shell ovate with a high spire and a moderately convex body whorl; apex missing in the type specimens, there being three whorls of the spire preserved; these spire whorls have a slightly convex profile between lined, distinct sutures; the surface is smooth with a faintly impressed band bordering the edge of the upper suture; trace of the lines of growth show a wide, _ back- ward curve or shallow sinus in the middle zone of the body whorl ; aperture is subovate, the end of the anterior canal broken: col- umellar area covered.
Length, 43.75 mm. (imperfect) ; diameter, 28 mm.
This species is based on two imperfect specimens, both with the anterior canal broken and their aperture so filled with matrix that the columella cannot be seen. The generic position of
259 CRETACEOUS OF PAITA: OLSSON 101
these shells is therefore uncertain and will remain so_ until better material is known. In form the shell strongly resem- bles certain smooth Fasciolaria such as the Recent Atlantic tulipa and distans. It is also possible that the species is a volutid comparable to the genus Ptychoris Gabb based on Voluta pur- puriformis Forbes*® from the Indian Cretaceous. From the Fusus difficilis d’Orbigny"’ of the Cretaceous of Quiriquina, referred by Wetzel”? to Leiostoma Swainson, the Peruvian species differs by its longer, straighter canal and less convex body whorl.
The Fasciolaria ? calappa Olsson from Monte Grande should probably be referred to the genus Lissapiopsis Imlay™* based on Lissapiopsis unicarinata Imlay from the Upper Cretaceous, Dif- inta formation of Mexico. Imlay considered this genus of large, shouldered gasteropods as related to Melongena but the group shows equally close resemblance to some members of the Strom- bidee.
Types —Paleontological Research Institution, Nos. 4950, 4951.
Occurrence.—Baculites zone.
Genus FUSINUS Rafinesque
Fusinus ? corbis, n. sp. Plate 9, fig. 15
Shell of medium size, solid, the spire longer than the canal; apex lost, the remaining whorls of the spire numbering about four; sculpture is formed by nine knoblike ribs which are strong- ly developed on the middle zone of each whorl and on the shoulder of the last whorl but fade out below on the base; in addition the entire surface is covered with coarse, cordlike spirals, fairly reg- ular in size except in the sutural zone where they are somewhat
70 Forbes, E.: Trans. Geol. Soe. London, vol. 7, 1846, p. 130, pl. 12, fig. 2; also Stoliezka, F,. Cretaceous fauna of southern India, vol. 2, 1868, Gastropoda, p. 91, pl. 8, figs. 4, 5, 6, 7.
71 d’Orbigny, A.: Voyage dans 1’ Amérique meridionale, 1842, Paleon- tologie, p. 118, pl. 12, figs. 11, 12.
72 Wetzel, W.: Die Quiriquina Schichten als Sediment und Palaontolo- gisches Archiv., Palaontographica, vol. 78, 1930, p. 69, pl. 11, figs. 3, 4.
73 Imlay, R. W.: Stratigraphy and paleontology of the Upper Creta- ceous beds along the eastern side of Laguna de Mayran, Coahuila, Mexico, Bull. Geol. Soe. America, vol. 48, 1937, p. 1843.
102 BULLETIN 111 260
smaller; anterior canal is long and straight but the end is broken in type.
Length, 49 mm. (imperfect) ; diameter, 25 mm.
Since the columella is covered, the generic position of this fossil is uncertain but its form and straight canal is similar to many species of true Fusinus. It also resembles a figure of a fusinid shell from the Maestrichtian of Persia referred to Lathy- rus, sp., by Douville™*.
Type.—Paleontological Research Institution, No, 4952.
Occurrence.—Baculites zone.
Superfamily VOLUTACEA Family VOLUTIDZE Genus VOLUTOCORBIS Dall
Volutocerbis meridionalis, n. sp. Plate 9, fig. 14
Shell subovate, the spire and aperture of about equal length ; nucleus lost on the type, the remaining whorls of the spire number about four; the sculpture is sharply subcancellate, formed by a series of narrow, ridgelike ribs which extend from the anterior canal to the suture and are crossed by strong spirals separated by wider interspaces; the ribs number 9 or 10 on the last whorl; sutures bordered on the anterior side by a strong cord or ridge; columella covered in the type.
Length, 35 5 mm.; diameter, 21.5 mm.
This seems to be a true V’olutocorbis, characterized by its fair- ly low spire and strongly cancellated sculpture. Volutilithes cf. crenulifera Bayan figured by Douville’® from the Maestrichtian of Persia is quite similar to the Peruvian but has a longer spire and more numerous ribs. Volutilithes crenulifera Bayan is an Eocere species referred to Volutocorbis by Cossmann™®, A
74 Douville, H.: Mission Scientifique en Perse par J. de Morgan, Etudes Géologiques, pt. 4, Paléontologie, 1904, p. 288, pl. 40, fig. 4.
75 Douyalle) Hi Loc: cit.. p. 290) pl. 40, igs8> 9:
76 Cossmann, M.: EHssais de Paléoconchologie comparée, vol. 3, 1899, p.
261 CRETACEOUS OF PaITA: OLSSON 103
Volutocorbis figured by White’ and referred to the Indian species Volutilithes radula Forbes from Pernambuco, eastern Bra- zil is perhaps a lower Eocene form.
T ype.—Paleontological Research Institution, No. 4955. Baculites zone.
Occurrence. Genus VOLUTA Linné Voluta inca, n. sp. Plate 9, fig. 8
The sheil is rather large, solid, with a shouldered body whorl and a medium high, conic spire; nucleus is missing, the spire whorls are sculptured with about to ribs which extend as low, narrow folds between the sutures; on the body whorl, these ribs occur on the shoulder angle only where they are large and prom- inent; general surface of shell smooth except for a few faint spirals bordering the upper suture; outer lip broken and columel- lar pillar concealed by matrix.
Length, 72.75 mm. (imperfect) ; diameter, 50.30 mm.
The type, the only specimen known, has a broken lip and the columella is covered with a film of rock matrix which cannot be removed, In form, however, the shell is distinctly volutid and there is little doubt that it belongs to this family.
Type.—Paleontological Research Institution, No, 4956.
Occurrence.—Baculites zone.
Genus LYRIA Gray
Lyria concha, n. sp. Plate 15, figs. 6, 7
Shell relatively small, solid, fusiform with a high spire and long aperture and canal; nucleus not preserved; spire whorls (five remaining on the type) have a low, convex form between strong, sinuous sutures; the surface texture appears solid, smooth, except for a series of strong ribs which number about eight on the last whorl; the ribs begin at the upper suture and extend across the base fading out’ on the canal; anterior canal, long, solid, the growth lines at the end becoming crowded and by their sinuous course show that the tip of the canal carried a small but
77 White, C. A.: Contributions to the paleontology of Brazil, Archivos
do Museu Nacional do Rio de Janeiro, vol. 7, 1888, p. 126, pl. 10, figs. 15, 1@, Wf
104 BuLuLeETIN 111 262
strong, siphonal sinus; columella straight with three small folds.
Length, 17.5 mm.; diameter, 9.1 mm.
Although fairly common, our specimens are all imperfect. One small shell shows three small, but distinct folds on the columella. The axial sculpture is formed by a series of slightly curved fold- like ribs, but the surface of the shell as a whole is smooth.
T ypes.—Paleontological Research Institution, Nos. 4957, 4958.
Occurrence.—Tortuga.
Class CEPHALOPODA Subclass TETRABRANCHIATA
Order AMMONOIDEA Suborder EXTRASIPHONATA
Family BACULITIDZE
Genus BACULITES Lamarck
Baculites lyelli d’Orbigny Plate 16, figs. 3-5 Baculites Lyelli d’Orbigny, 1847, Voyage au Pole Sud et dans 1’Océanie sur les corvettes L’Astrolabe et La Zélee pendant les années 1837- 1838-1839-1840 sous le commandement de M. Dumont-d’Orville eapi- taine de vaisseau. Geologie Atlas, pl. 4, figs. 3-7.
Fragments of a large baculite are common in the Upper Breccia or Baculites zone and this notice is probably the first record of the occurrence of species of this genus in Peru. Baculites has been repeatedly recorded from the Upper Cretaceous of Chile and Argentina. Darwin obtained specimens from Tomé in the Bay of Concepcion which were figured by Forbes’* in the Appendix to Darwin’s Geological Observations who referred them to the In- dian species, Baculites vagina. About the same time other spec- imens, which were collected by members of a French expedi- tion, were beautifully figured by D’Orbigny as Baculites Lyelli and ornatus in the plates of the Voyage of the Astrolabe but without accompanying description and their exact local- ity is not known. The Chilian species has been carefully studied
78 Forbes, E.: Descriptions of secondary fossil shells from South America, Appendix to Part 2 of Darwin’s, Geological Observations, 1846, pl. 5, fig. 3.
263 CRETACEOUS OF PaITA: OLSSON 105
by Steinmann’® and later by Wilckens*®, both authors followed Forbes in referring the South American forms to the Indian species. This view was also shared by Kossmat*?. The most recent studies of this group is by Paulcke** who separated two species mainly from characters of the suture lines, referred one form to the European Baculites cf. anceps Lamarck and described the other as Baculites vagina var. cazadorianus. Another baculite has been described by Weaver** as Baculites argentinicus. Weav- er’s two specimens were very fragmentary and are said to have been collected together with a typical Roca molluscan fauna con- taining Cardita beawmonti. Weaver considered his species most closely related to anceps but made no comparison with the other described South American forms. Gerth** considered Weaver’s collection as containing a mixed Roca and Malargue fauna. D’Orbigny’s beautiful figures of Baculites lyelli and ornatus are apparently restorations. Baculites ornatus differs from lyelli by its stronger sculpture, each rib being binodal and the siphonal side is wider or more flangelike. There are also differences in the sutures, the most striking being a lower, wider or more spreading siphonal saddle and narrower first lateral lobe. These differences would seem sufficient to establish these two forms as good species. Sutures of the Chilian baculite figured by Stein- mann*® as Baculites vagina are essentially similar to /yelli and to
79 Steinmann, G.: Die Cephalopoden der Quiriquina-Schichten, N. Jahrb.
Min., BB. vol. 10, 1895, p. 89, taf. 6, figs. 4a, 4b, 4c, 4d, and 4e; also text figures 8-12.
so Wilekens, O.: Revision der Fauna der Quiriquina-Schichten, N. Jahrb. Min, BB. vol. 18, 1904, p. 188.
81 Kossmat, F.: The Cretaceous deposits of Pondicherri, Records, Geo- logical Survey of India, vol. 30, 1897, pt. 2, p. 73.
82. Pauleke, W.: Die Cephalopoden der oberen Kreide Sitidpatagoniens,
Berichten der Naturforschenden Gesellschaft zu Freiburg i. Br. Band 15, 1906, pp. 10, 11, pl. 16, figs. 5, 5a, 5b, 6, 6a.
838 Weaver, P.: Roca formation in Argentina, Amer. Jour. Sci., ser. 5, vol. 13, pp. 429-434, figs. 2a-c; also 1931, Paleontology of the Jurassic and Cretaceous of west central Argentina, Univ. of Washington, Mem., No. 1, 1927, pp. 466-467, pl. 62, figs. 401, 402, 403.
‘84 Gerth, H.: Geologie Stidamerikas, vol. 2, 1935, p. 327.
85 Steinmann, G.: Loe. cit.
106 BULLETIN 111 264
Fig. 1. Sutures of Baculites lyelli d’Orbigny. Drawn from specimen on Plate 16, figure 2.
our specimens from Peru, and it is evident that they all belong to the same species. Both the Chilian and Peruvian forms have a long narrow medially divided siphonal saddle bordered by a wide lateral lobe. The sutures of typical Baculites vagina from India as figured by Forbes and Kossmat, taking into account minor differences probably due to age, show a general likeness to the South American species and thus indicate a real relationship be- tween these widely separated forms. However, there are definite differences in sculpture. Although Kossmat*® considered the Indian and South American forms as one species, he also noted these differences as may be seen from his quotation: “The Chilian Baculites vagina is recognizable by the fact that the swellings of the ribs are a little nearer to the siphonal part of the shell than in the Indian type, for this reason the section appears to be more oval. This peculiarity may be constant as I observed it also in Chilian Baculites of this species in the British Museum but I did not attach much value to it then as the specimens in question were not adults,” (p. 73). Until abundant material from South Amer- ica and India are available for detailed study and evaluation of all characters, it seems best to consider these differences as spe- cific and to restrict the use of the name vagina to the Indian forms. The South American forms must therefore take D’Or- bigny’s name Jyelli.
Our specimens are mostly fragments of the living chamber with a pebbly matrix filling the interior. Two fragments of the
86 Kossmat, F.: Loc. cit.
265 CRETACEOUS OF PaITA: OLSSON 107
same individual when united have a length of 330 millimeters and a diameter of 40 millimeters at the larger end. The section of the conch is subtrigonal, the immature portion has more convex sides than the adult. The antisiphonal side is flattened to de- pressed in the middle but as the result of compression the sides are usually distorted. The surface sculpture consists of strong, foldlike ribs or swellings on the siphonal side of the middle, over which the lines of growth cross in an oblique, coarse fashion. ‘These characters in our specimens seem to be constant.
Figured Specimens.—Paleontological Research Institution, Nos. 4960, 4961.
Occurrence.—Baculites zone.
Family TURRILITIDX
Genus TURRILITES Lamarck
Turrilites peruvianus, n. sp. Plate 17, fig. 4
Helicoceras, sp., Olsson, 1934, The Cretaceous of the Amotape Region, Ode Citic 19> (ei, oll, 10), sila,
A single specimen from the Baculites zone is a fragment pre- serving the last turn. It is the same species as previously re- corded from Monte Grande as Helicoceras, sp. Coiling sinistral, loose ; sculpture consisting of two rows of spinelike nodes, the su- perior set placed a little above the middle, the lower set on the outer border of the base; above and between these rows, the surface is smooth; there are a few irregular ribs which near the aperture cross the face of the whorl but they are generally present only in the umbilical area.
Height of fragment, 25 mm.; diameter, 31 mm.
Type.——Paleontological Research Institution, No. 4870.
Occurrence.—Baculites zone.
Family DESMOCERATIDZ
Genus PARAPACHYDISCUS Hyatt Parapachydiscus, sp. Plater Gaeties ad! Our single specimen, a fragment of the last whorl, has a di- ameter of 89 mm. The shell is strongly compressed, its thickness
108 BULLETIN 111 266
being only about 20 mm. The ornamentation consists of ribs of two sizes; a primary set extends from the umbilical angle to the middle of the venter and numbers about Io to a half turn and a shorter secondary set, usually one, sometimes two in each pri- mary interspace strengthen the sculpture in the peripheral portion. The form and sculpture of this Parapachydiscus are similar to certain species from the Sphenodiscus beds of eastern Brazil de- scribed by Maury*? amongst which may be mentioned the Pay- apachydiscus dossantosi and endymion. No trace of the suture lines are preserved on our specimen. Specimen figured.—Paleontological Research Institution, No. 4962. Occurrence.—Baculites zone. Family ENGONOCERATIDZE Genus COAHUILITES Bése
Subgenus AUSTROSPHENODISCUS, new subgenus
Genotype.—Sphenodiscus pleurisep.a Conrad var. peruviana Gerth The following is a description of the subgenus 4ustrospheno- discus : Shell sphenodiscoid with a sharply keeled venter; suture is like Coahuilites in having the external saddle divided into two
Fig. 2. Sutures of Coahuilites ( Austrosphenodiscus) peruviana Gerth.
Fane s : : ae Taken from specimen figured on Plate 17, figure 1. 7 « ce a WG Vn 1p - T 1 7 Bf Maury, C.: Cretaceo da Parahyba do Norte, Servigo Geologico e Mineralogico do Brasil, Monographia No. 8, 1930.
267 CRETACEOUS OF PAITA: OLSSON 109
(not three) branches by an adventitious lobe which is nearly as deep as the lateral lobe; in addition, the first branch or adventi- tious saddle is again subdivided into two secondary branches ; sad- dles with phylloid ends.
Remarks.—tThe suture, here figured, was drawn from the spec- imen illustrated on Plate 17, fig. 1. Its pattern is essentially simi- lar to that shown in Gerth’s drawing (fig. 4, p. 238). The ex- ternal saddle is divided into two branches by a deep lobe which nearly equals the lateral lobe in width and depth. This character is typical of Coahuilites** (genotype Coahuilites sheltoni Bose) from the lower Escondido of northern Mexico while in true Sphenociscus Meek there are three adventitious branches in the external saddle. In addition, this species shows the peculiarity of having the first branch further subdivided by a smaller sub- adventitious lobe into two smaller branches, the ventral arm of which is sharply inclined towards the venter, This character is not only constant for the Peruvian species but is shared by an un- described species in our collection from the Lower Umir of Co- lombia and consequently has more than specific value. The differ- ent branches of the external saddle are indented by several short lobes, the saddles having phylloid outlines.
Typical Coahuilites is known from several localities in beds of lower Maestrichtian or Campanian age in Colombia and Vene- zuela. According to Hedberg*®, Coahuzlites on basis of specimens identified by Spath, occurs in the Rio de Oro formation of north- eastern Colombia. An undescribed species has been collected from the Mito Juan of Tachira and several crushed speci- mens which may belong to Coahuilites are known from the lower Umir of the Magdalena Valley.
Coahuilites (Austrosphenodiscus) peruviana Gerth lelleeey A, eS M2 Sphenodiscus pleurisepta Conrad var. peruviana Gerth, 1928, Leidsche geol. Mededeel., deel 2, pp. 237, 238, text fig. 4.
This species is represented in our collection by two specimens,
88 Bose, E.: Cretaceous ammonites from Texas and northern Mezico, Univ. of Texas, Bull. No. 2748, 1927, pp. 279-283.
89 Hedberg, H. D., and Sass., L. C.: Synopsis of the geologic forma- tions of the western part of the Maracaibo Basin, Venezuela, Boletin de Geologia y Mineria, Caracas, Venezuela tomo 1, 1938, p. 86.
110 BULLETIN 111 268
the larger and more perfect one being here figured. This shell measures as follows:
Greater diameter, 86 mm. (partly restored)
Lesser diameter, 66 mm.
Thickness in umbilical region, 15 mm.
Height of whorl, 53.5 mm.
The shell is discoidal, laterally compressed, very involute and with a sharply angled or keeled venter. The surface is smooth with no indication of nodes or ribs. Cross section of the last whorl is narrowly lenticular, a little wider on the umbilical side of the middle; umbilical region is not noticeably impressed ; suture as described above.
Remarks.—Gerth in his discussion of this species stated that his collection contained 80 specimens, represented mostly by frag- ments of the living chamber but also included a few perfect in- dividuals. Gerth considered peruviana as a variety of the Texan Sphenodiscus pleurisepta Conrad basing his opinion largely from the ribbed sculpture of many specimens. According to our stud- ies on material from the same locality, the ribbed forms belong’ entirely to the new genus described here as Paciceras. Eliminat- ing these forms, the few remaining specimens belong to a smooth species with a narrow cross section. The sutural pattern of this species agrees with that described by Gerth for peruviana. It is obvious that peruviana is not closely related to Sphenodiscus pleurise pta.
Specimen.—Paleontological Research Institution, No. 4867.
Occurrence.—Basal or Sphenodiscus beds, La Mesa.
Genus PACICERAS, new genus Genotype.—Paciceras pacificum, n. sp.
The following is a description of the genus Paciceras :
Sphenodiscoid, involute with a sharply keeled venter and small umbilicus; umbilical region impressed, bordered by a circle of small nodes or stronger ribs; sutural pattern relatively simple; the umbilical saddles are fairly numerous with flattened to rounded summit outlines, the separating lobes shallow and weak- ly toothed; the lateral saddle wide, bipartite, divided by an ad-
269 CRETACEOUS OF ParTA: OLSSON ibatil
ventitious lobe ; lateral lobe moderately deep and strongly toothed.
Remarks.—This genus is closely related to Lybicoceras®® ** (genotype Sphenodiscus Ismaeli Zittell)®* from the Maestrich- tian of the Libyan desert and of which two species are known. The main differences are in the sutural pattern. In Paciceras the siphonal saddle is less deeply divided by the adventitious lobe and the series of umbilical saddles are more flattened. The form and external sculpture are similar.
Paciceras pacificum, n. sp. Bilatem li ess OO
Adult shell of medium size, strongly involute and _ thickly lenticular; umbilicus small, deep with the surrounding area strongly impressed and bordered by a circle of small nodes num- bering about 14 or 15 to each turn; these nodes may be quite strong or only faintly indicated; a second circle of nodes is some-
times present nearer the venter but otherwise the surface is smooth ; venter is sharply angled or keeled; in cross section the outer whorl is broad, its width about half its height as measured from the umbilical center to the ventral edge; sutural pattern as
90 Hyatt, A.: Pseudoceratites of the Cretaceous, Monograph of the U. S. Geol. Survey, vol. 44, 1903, p. 57.
91. Roman, F.: Les Ammonites Jurassiques et Crétacées, Essai de Gen- era, 1938, p. 494, pl. 51, figs. 473, 474.
92 Quass, A.: Beitrag zur Kenntnis der Fauna der obersten Kreide- bildungen in der libyschen Wiiste, Paleontographica, vol. 30, 1902, pp: 302-307, taf. 29, figs. 3-7, and taf. 30, figs. 1, la-b.
, BULLETIN 111 270
described for the genus is relatively simple, its most characteristic feature being the low, flat-topped, umbilical saddles and toothed lobes; the inner portion of the suture is not exposed on available material but in the figured pattern, there are six umbilical saddles shown; the lateral lobe is moderately deep and strongly toothed ; the lateral saddle is wide and medially divided by a shallow adventitious lobe; siphonal saddle broad, flat.
Greater diameter, 73 mm.; thickness of last whorl, 22 mm.
This is the commonest ammonite in the Austrosphenodiscus beds at La Mesa and will be recognized by its form, sculpture and pattern of its suture.
T ype.—Paleontological Research Institution, No. 4868. Occurrence.—La Mesa. Paciceras gerthi, n. sp. Plate 16, figs. 6, 7
Adult shell of medium size, involute, more thickly lenticular than pacificum and more strongly ribbed venter sharply keeled; umbilical region flatly impressed; the sculpture is formed by a set of medium strength ribs which are developed in the middle zone between the impressed umbilical area and a narrow, smooth band bordering the keeled venter; the ribs would number about 14 to a complete turn and are nodose at the ends; sutural pat- tern essentially similar to pacificum.
Since no perfect specimen is available, the following measure- ments are partly estimated:
Greater diameter, +65 mm.; height of last whorl, 40.5 mm.; width of last whorl, 21 mm.
Type.—Paleontological Research Institution, No. 4963.
Occurrence.—La Mesa.
PLATES PLATE 1 (8)
Plates furnished gratis by the author ready for insertion.
114 BULLETIN 111 272 EXPLANATION OF PLATE 1 (8)
Figure Plate
ipeInocerantuss Sp.) bee eee eee 39
Length, 110 mm. Pe RI.) Nos 48210" Baculites zone. OP MNO CEEAMIUS Uys sue Ae eee ee i gid ia 38 Length, 110 mm. PR. a: No. 4809: Baculites zone. 3) Macrodonax: peruviana, Na Sp. 22 ee 62 Holotype, length, 118 mm. alee No Sele Baculites zone.
4. Macrodonax: peruviana, ni. Sp. 222. ee Eee 62 Drawing of hinge of holotype. 5eOstréar palpay prise coe A ee 40
Holotype, left valve, length, 16 mm. Baal Noms 0.55
Tortuga.
6, Ostreapalpay tn. “spy t-- 4 ee ee 40 Holotype, right valve. Tortuga.
f: Ostrea) (voepha)sechura, ia Sp. 2.2 ee eee Al
Holotype, length, 88 mm. P. R. I., No. 4804. Baculites zone. 8. Ostrea (Lopha) sechura, n. sp. —— a Nee OY ts re 41 Interior of holotype.
116
BULLETIN 111 274
EXPLANATION OF PLATE 2 (9)
Figure Plate
ile
. Roudaireia peruviana Olsson
Pseudocuculleza gregoryi Olsson 31 Length, 140 mm. P. R. L., No. 4820. Baculites zone.
. Pseudocucullza cregoryi Olsson 2 eee 5 oil
Same specimen as last, figured to show hinge.
> Pseudocucullza \paitana,ns sp eee eee 31
Holotype, length, 79 mm. POR: TE No. 4821. La Mesa.
= Pseudocucullza) paitanas on. Sp 6 wee 31
Paratype, length, 71 mm. P. BR. 1., No. 4822. La Mesa.,
} Pseudocucullza ‘paitana, mn. Sp, eee eee 31
Paratype, length, 62 mm. P. R. I., No. 4823. La Mesa.
Length, 94 mm. P. R. I., No. 4824. Baculites zone.
2 Roudairela peruvianay Olsson) Eee 45
Length, 72 mm. Darvas NOs 4820: Baculites zone.
> Keanotia pacifica on. Sp. 8 2.+ eee 58
Holotype, length, 76 mm. Pees Noi48265 Baculites zone.
’
®
118 BULLETIN 111 276 EXPLANATION OF PLATE 5 (10) Figure Piate
1. Trigonia: hopkinsi, nn. sp; 2: ee Holotype, length, 83 mm. PER. Nios 489) Baculites zone.
2. Breviarca peruviana,, n. sp. 22. eee 35 Paratype, length, 23 mm. P. R. I., No. 4815. La Mesa.
32 Periploma nermeta, n. Sp. ----22= 2 eee 44 Holotype, length, 66.5 mm. IPS Re de Nor 4818: Baculites zone.
4, Trigonia (Scabrotrigonia) gerthi, n. sp. — 42 Holotype, length, 56 mm. PS RL Nos 4812: Baculites zone.
5. Trigonia (Scabrotrigonia) gerthi, n. sp. eee 42 Paratype, length, 54 mm. Pe Rae, Now 4813: Baculites zone.
6. Peruarca’ pectunculoides; ny spe ee 33 Holotype, length, 50 mm. 12, 1s Mos INOS eke le/ Baculites zone.
ie Peruarcay pectunculoides;, ne Spy 22 ee 33 Same specimen as last.
8." Breviarca ,peruviana,on. SP. 22. eee eee 35 Holotype, length, 18 mm. P. R. I., No. 4814. La Mesa.
9. Breviarca peruviana, n. sp. _ 85 Paratype, length, 18 mm. IPS Ra Le Nos 48:16: La Mesa.
10. Trigonia (Scabrotrigonia) gerthi, n. sp. — 2 42
Same specimen as figure 5,
Pu. 10, VoL. 28 Buu. AMER. PALEONT. No. 111, Pu. 3
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120
BULLETIN 111 278
EXPLANATION OF PLATE 4 (11)
Figure Plate
1
10.
. Corbicula meridionalis, n. sp.
. Panopea frailia, n. sp.
Incanopsis. acariformis, nm. Sp. 2. 2 eS eee 35 Paratype, length, 17 mm. P. KR. 1., No. 4833. Tortuga.
. Incanopsis acariformis, n. sp. <..2...2 2 eee 35
Holotype, length, 17.75 mm. Po RE, No. 4832. For exterior of same specimen see Plate 5, fig. 8.
Holotype, length, 37 mm. P. R. I., No. 4834. Tortuga.
. Corbicula. meridionalis; n. sp. 2.2 EEE AT
Paratype, figured to show hinge, length, 34 mm. P. R. L., No. 4835.
Tortuga.
, Antigona: speciosa, n. Sp. 22-2: 2 Eee 56
Holotype, length, 21 mm. P. R. T., No. 4836. Tortuga.
, Antigona “speciosa, N. Sp. .22422.2.0 EEE eee 56
Paratype, length, 16 mm. P. RB. 1., No. 4838. Tortuga.
. Antigona speciosa TU SD sae at ee ke ee eae eS 56
Paratype, length, 18 mm. Pala lew Non 483i. Tortuga.
. Ostréa, palpa; ne spi ee wit 40
Paratype, length, 34 mm. P. R. I., No. 4806. Tortuga.
Holotype, length, 98 mm. P. R. I., No. 4839.
Ostrea pallpa;, ‘ni-Sp. 2 ee eee 40 Paratype, height or length, 18 mm.
Figured to show the crenulated margins adjacent to the hinge. Tortuga.
No. 111, Pu. 4
Buu. AMER. PALEONT.
Pt. 11, Vou. 28
Panty a
ie Mh Uy, ai, i Ky i Malt Zh im! ny ve 4 ,
Ve SME, Vit a ‘ \ , ‘ hon Ua oN ae i
PLATE 5 (12)
122 BULLETIN 111 280 EXPLANATION OF PLATE 5 (12) Figure Plate
1. Cardium (Perucardia) briiggeni, n. sp. ---.-------—--------_----_----__-- 52 Holotype, height, 106 mm. P. R. 1., No. 4827. Baculites zone.
2. Cardium (Incacardium) mellisum, n. sp. —----------------------------— 53 Holotype, length, 34 mm. Showing hinge of right valve. P. R. L., No. 4830. Tortuga.
3. Cardium (Perucardia) briiggeni, n. sp. -------—------------------------------— 52 Paratype, length of hinge fragment, 50 mm. The broken hinge of the right valve shows only the roots and
stumps of the strong cardinal and posterior lateral tooth.
P. R. I., No. 4827a. Baculites zone.
4. Cardium (Incacardium) mellisum, n. sp. —------—------ 53 Paratype, length, 37.5 mm. 125 It, ls, IN@, Zeal Tortuga.
5. Cardium (Perucardia) briiggeni, n. sp. — 52 Fragment of shell showing position of spines. P. R. L., No. 4828. Baculites zone.
6. Cardium (Incacardium) mellisum, n. sp. 53 Holotype, length, 34 mm. JES lets Ie, INNO, ZYseX0), Tortuga.
7. Cardium (Perucardia) briiggeni, n. sp. 52 Paratype, height, 103 mm. P. R. L., No. 4829. Baculites zone.
Sylncanopsis) acariformiss, my spi 35
Holotype, length, 17.75 mm.
Same specimen as Plate 4, figure 2. POR, Nos 48325
Tortuga.
Buu. AMER. PALEONT. No. 111, Pu. 5
Pu. 12, Vou. 28
PLATE 6 (13)
. Tellidora (Tellipiura) peruana, n. sp. —--—-----—--—----—------—----— 63 Holotype, length, 26 mm. 12s TR Mos IN@s GxSHE(c Tortuga.
. Tellidora (Tellipiura) peruana, n. sp. -—-.-.____--_---_—_—---____---—----- 63 Tortuga.
. Tellidora (Tellipiura) peruana, n. sp. --.---------—-----—__—-----—---_--_- 63 Paratype, length, 22 mm. Pe Rae NO W4:84-9. Tortuga.
fhellidora ¢(Lellipiura)) peruana..n) Ss). _ 63 Paratype, length, 25 mm. P. R. 1., No. 4848. Tortuga.
124 BULLETIN 111 282
EXPLANATION OF PLATE 6 (13)
Figure Plate
1. Corbula broggii, n. sp. __ epee ee. A eee a _ 65 ee length, 31. 50 1 mm. . R. L, No. 4840. ee zone. 2) Corbula’ brogell).n: Spo ee eee Same specimen as last. 3. Corbula broggii, n. sp. —- ee Same specimen, dorsal view. 4. Gervilia incertans, n. sp. = Sate ves en Holotype, length, 30 mm. P. R. 1., No. 4845. Tortuga. 5s Amatimyas, (Sp... q2222! <. S e e ee Length, 25 mm. P. R. I., No. 4850. Tortuga. GS CAM atimy. ase Sp ss xe ae eee Length, 18 mm. P. R. 1., No. 4851. Tortuga. tT. Mulinoideés. chicama,,. ni. spi >. a eee Holotype, length, 22 mm. P. R. 1., No. 4852. Tortuga. 8. Corbula tuma, n. sp. _ _ Nel ee ee ee eS oy Paratype, length, 10.5 mm. 12% Lit, Ma, INO: "4841, Tortuga. 9} Corbulactuma,. mn. sp. <=. eh ee Paratype, length, 10 mm. P. R. L., No. 4842. Tortuga. 10. Corbula tuma, n. sp. i eee ee AN 2c ee 65 Holotype, length, 11 mm. 15 We das INO, 4843, Tortuga. 11. Corbula tuma, n. sp. ee ee eS Paratype, length, 10— mm. P. R. I., No. 4844. Tortuga. 12. Legumen peruvianum, n. ST ae en a ee ee 58 Impression of the left valve. Holotype, length, 41 mm. PR. Ee, No: 74846: Tortuga.
. 65
38
44
. 44
Buu. AMER. PALEONT. INVO)y WILLS Verne
Pu. 13, Vou. 28
UNL adee ede 3
Sars § id Pein i i ; ; a tpi PAR ab Ay YY
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iy
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AGL a Ny ve H ir " ; ae
PLATE 7 (14)
126
BULLETIN 111 284
EXPLANATION OF PLATE 7 (14)
Figure Plate
1. Aphrodina pacifica, n. sp. _.—----.---------—------------_____----- = 54
. Aphrodina (Sechurina) australis, n. sp. ——----------------.- 57
Holotype, length, 68 mm. P. R. L., No. 4857. Baculites zone.
, Aphrodina pacifica, nm. Sp) 222 54
Same specimen as last.
Paratype, length, 86 mm. P. R. L., No. 4859. Baculites zone.
. Mulinoides-chilca, n.. sp. eee 61
Paratype, figured to show lunule. 125 Je Is IN@s GE, Baculites zone.
. Aphrodina (Sechurina) australis, n. sp. ~~. 57
Holotype, length, 68 mm. P. R. L., No: 4858. Baculites zone.
. Aphrodina (Sechurina) australis, n. sp. —-- ~~~ 57
Same specimen as figure 3.
se lulinoides|chileat on. (Sp. (eee 61
Holotype, length, 51 mm. P. R. I., No. 4854. Baculites zone.
» Mulinoides\ chilea; in: sp... eee 61
Paratype, length of hinge portion figured, 32 mm. Be Re ds) Nom 4850: Baculites zone.
> Mulinoides \chilea,, n),.sp..'--22 ee eee 61
Paratype, length of hinge portion figured, 34 mm. P. R. 1. No. 4856. Baculites zone.
Pu. 14, Vou. 28 BuLu. AMER. PALEONT. No, Ti) Pit
| 1 mn | } Wid HARD } ay ; 1) a) Atte aymey it) RRO IRA KT AIS CAEL"). REPL
My ah oe
yn
BULLETIN 111 286
EXPLANATION OF PLATE 8 (15)
Figure Plate
1. Sauvagesia peruviana, n. sp. a eS
Holotype, greater diameter, 340 mm. P. R. L., No. 4800. Radiolite sandstone, Tortuga.
. Sauvagesia peéeruviana, mn. Sp. 2222.22. eee 48
Lower side of a separated plate from the outer wall, length, 170 mm.
Pas ey eNom 48005
Same locality.
/ Sauvagesia. peruviana, n: Sp... ee ee eee 48
End view of lower fragment of the holotype showing the low growth form and section of body cavity.
} Sauvagesia peruviana, n. Sp. —..-\.. 2 eee 48
Paratype, length, 165 mm. A smaller, colonial form. Pp. R. L., No. 4802.
. waulvagesiaperuviana; on? Sp... 2 ae ee eee 48
Separated individual, probably once colonial, length, 115 mm. Peele Nos 4803: Radiolite sandstone, Tortuga.
Pu. 15, Vou. 28 BuLL. AMER. PALEONT. No. 4411, Pris
PLATE 9 (16)
wiCalyptreavapertas colander: 22. ee a eee ee 0) Greater diameter, 25.5 mm,
P. R. 1., No. 4935. Tortuga.
“ Calyptrea caperta. Solander. 2222.0. 2 2 eee ee 90 Greater diameter, 35 mm. Rane eNO 49368 Tortuga.
. Volutocorbis meridionalis n. sp. Holotype, length, 35.5 mm.
Py Rel Nos 4950; Baculites zone.
SIE USINUS) CORDIS; pL uS Dn, oa eases ne eee ees Lee es en Ne 101 Holotype, length, 49 mm.
Pana NOwAa 9 o2e Baculites zone.
130
BULLETIN 111
285
EXPLANATION OF PLATE 9 (16)
Figure
il
10.
ale
. Ampullina breccia, n. sp.
Ampullina itortuga, Nn) spy 22)
Holotype, length, 56 mm. P. RT, No. 4947. Tortuga.
. Ampullina breccia, n. sp. -—-~. --..-------
Holotype, length, 58 mm. Pens hs No: 4944; Baculites zone.
Paratype, length, 41 mm. P. R. 1, No. 4945. Tortuga.
. Ampullina breccia, n. sp. —
Paratype, length, 47 mm. P. R. I., No. 4946. Tortuga.
. Ampullina cumara, n. sp. —-----.------
Holotype, length, 29.5 mm. 125 1k Ii, INO, 2A. Tortuga.
. Nerita jayanca, n. sp. ——..-......___.
Paratype, height, 8.25 mm. iP. RL, No: 4876: Tortuga.
-eNeritas jayanca, n. sp.
Holotype, height, 8 mm. Po R. L., No. 4875. Tortuga.
s Volutayinca, n: sp. Holotype, height, 72.75 mm.
Ree Now 4956: Baculites zone.
. Tectus tschudi, n. sp.
Holotype, height, 18.5 mm. Pp. R. E, No. 4874. Baculites zone.
Calyptrea aperta Solander —_
Greater diameter, 24 mm. P. R. I., No. 4934. Tortuga.
Calyptrea aperta Solander —._
Greater diameter, 24 mm. 12S 1k, Ii, ING, COB
pee i
Se ee ee 97
ee A 5 ESS
bt Mae ee 67
Ee 67
403 EE 103
ie EE 66
ie ee 00
Eocene, Parinas sandstones, Keswich Hills, Negritos.
Pu. 16, Vor. 28
Buu. AMER. PALEONT.
iM
\ Aa } NA ant Nie hi L A ' if ; ; AN tet
RB AN Shy ay sien’ iva
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PEATE 10" (17)
125 Turritellavsaposason:: Sp. es =) ee ee ee Paratype, length, 19.75 mm. Pie Nos 48 oie Tortuga.
13 ehurritellaprechira, nsisp.2s2 > ee eee 72 Holotype, length, 31 mm. P. R. I., No. 4892. La Mesa.
132 BULLETIN 111 290
EXPLANATION OF PLATE 10 (17) )
Figure Plate
1: Mesaliatvqanja,onsvsps.co ato en ee 2 aie 2 68 Holotype, length, 25 mm. PRS Ie No; 4879" Tortuga.
2. Mesalia’ janja; nuisp: 2-2 eee 68 Paratype, length, 25.5 mm. P. R. L., No. 4880. Tortuga.
33: Mesalia: janja; ins Sp. 2) a ee eee 68 Paratype, length, 27 mm. P. R. L., No. 4881. Tortuga.
4.. Turritella.saposa; nm: ‘Spy 2.2... eee Holotype, length, 26 mm. PR. I Now 488i Tortuga, lower zone.
5. Lurritella lama; ns sp.: 22s2s-- ee eee 70 Holotype, length, 25 mm. P. R. 1., No. -4884. Tortuga.
6; Turritella isaposa; n. sp. 22-0. eee eee eT Paratype, length, 24.5 mm. Relea Now 4888: Tortuga.
"; (urritella: ‘saposa;.'n..-Spy 2-3-5 eee Thal Paratype, length, 21 mm. Pe Rs de Nos 4889: Tortuga.
8: ‘Lurritella lama, nicsps 2:22... 2 eee 70 Paratype, length, 19.5 mm. Ra its, les Nos 4880: Tortuga.
9. Turritella-saposas ins '8pi. 2 2. al ee Paratype, length, 18.5 mm. - P. R. I., No. 4891a. Tortuga.
10. Turritella lama, n. sp. — ab Spat Se es ee nC Paratype, length, 18 mm. Reo. Jes Now 4886: Tortuga.
11. Turritella saposa, n. sp. fh ee TET Paratype, length, 21 mm. P. R. L., No. 4890: Tortuga.
12.
13.
14.
15.
PLATE 11 (18)
Turritella parinensis, n. sp. —— : ee Yh Holotype, same specimen as figure. 2, ‘slightly ‘different view to show the form of the growth lines. Sechuritella, chacapoya, on: sp.) 2 eee reer 77 Paratype, length, 41 mm. PPR. Now 4909: Baculites zone. Sechuritellamterebracinctay nous) ie ee rit Paratype, length, 62 mm. P. R. L., No. 4907. Baculites zone. Turritella ceiba, n. sp. SEEING Ge I eso eS Oe eees Seam Holotype, length, 114 mm. P. R. 1., No. 4894. Baculites zone.
134 BULLETIN 111 292 EXPLANATION OF PLATE 11 (18) Figure Plate
1s) Rurritella, parinensis;. ns SDs) oc nT Paratype, length, 46 mm. Pe Rae Non 4898: Cabo Blanco (Parinas sandstones).
2: Turritella: parinensis, n: iSp..l2- = eee 75 Holotype, length, 52.5 mm. Re Re Nos 4897, Parinas sandstones, Parinas Point.
3. Woodsalia paitana robusta, n. subsp. —___.------.-.------------------- 70 Paratype, length, 42.5 mm. Pee Rae le Nos 4899: Tortuga.
4Sechuritella chacapoya\ jn. (Sp. eee Tt Holotype, length, 54 mm. P. R. L., No. 4908. Baculites zone.
5: \Woodsalia’ paitana; n. Sp... 22. EE 69 Holotype, length, 47 mm. Re Re Te Non 4882° Tortuga.
6. Turritella ceiba, n. sp. — aie Se ie Ne 72 Paratype, length, 33 mm. Paka Niow 48935 Baculites zone.
feasechuritella, terebracinctas) ny Sp) eee AE Paratype, length, 60 mm. PPR len Nom 4903: Baculites zone.
8: Sechuritella’ terebracincta, n. sp; 2.5520. Se eee Paratype, length, 35 mm. P. R. 1., No. 4904. Baculites zone.
9. Woodsalia paitana robusta, n. subsp. — 70 Holotype, length, 35 mm. 32 WR, Moy INO, Ges By Tortuga.
10. Sechuritella terebracincta, n. sp. —.—— 17 Holotype, length, 43 mm. P. R. 1., No. 4905. Baculites zone.
115 Sechuritella terebracincta; ns sp. 2 aa
Paratype, length, 28 mm. P. R. I., No. 4906. Baculites zone.
Buu. AMER. PALEONT.
No. 111, Pu. 11
ThE isp ie RN Tt, K f ae mt
Atay, Ay 1. A Las La sae a ia unl VA; nu 4 wi nm ne fi ' a !
13.
14.
15.
16.
Ife
PEATE 12) G19)
Glorioclava~inca,, ns, Sps 2a = ee ee ee ee 86 Holoytpe, length, 37 mm. P. R. L., No. 4925. Tortuga.
Nodifaunts costatus, n. sp. 2 ee ee 8 Holotype, length, 31 mm. P. R. I., No. 4923. Tortuga.
Stalioa agnia, n. sp. SNS uel) ote in has SE a ee Seg rp 67 Paratype, length, 3 mm. Pe Rs 1, Nos 4877 Tortuga.
Stalioa; agnia; ny sp, 222 Soe Se ee Se ee 67 Holotype, length, 3 mm. Pe Re; No 4878: Tortuga.
Pseudomelania simplex, n. sp. Ph ipeon jeu s i 66 Holotype, length, 18 mm. Peele NOmASiioe Tortuga.
136 BULLETIN 111 294
ExPLANATION OF PLATE 12 (19)
Figure Plate i. Previcarya. peruviana, nm: isp. 22.2252 See eee 87
Holotype, length, 35 mm. P. R. L., No. 4926. Tortuga. 2. Previcaryaperuviana, nn: (Sp. 2... 2 eee eee Ree = 87 Paratype, length, 36.5 mm. P. R. L., No. 4927. Tortuga. 3. Previcarya ‘peruviana,-n; sp) =) Eee eee 87 Paratype, length, 24 mm. Pp. R. L., No. 4928. Tortuga. 4; Patinana americana; ‘n. Sp. 224 8 eee eee 90 Holotype, length, 15 mm. P. R.1., No. 4929. Tortuga. 5; Stalioa ‘agnia, <1.) Spi 2222-2 ee 67 Paratype, length, 2 mm. JP dit, Mos INOS 44S fe Tortuga. 6; Nodifaunus nodosus,)n. sp o22:2-.4 Eee 84 Holotype, length, 34 mm. Pp. R. I., No. 4920.
Tortuga.
i, Nodifaunus ‘nodosus;;n. Sp.) 2.2222 3. eee 84 Same specimen as last.
8. Melanatria: medialis, n. sp... se Eee 78
Holotype, length, 28.5 mm. PA Non 4910s Tortuga. 9. Nodifaunus costatus, n. sp. iii) . 85 Paratype, length, 23 mm. P. R. 1., No. 4924. Tortuga. 10. Nodifaunas: nodosus, in. sp. 2. eee 84 Paratype, length, 26 mm. 12, Jiy dhs INOS CePA Tortuga. 11. Melanatria: medialis; n..‘sp. .222220.222 = eee ee? i8 Holotype, length, 28.5 mm. Same specimen as figure 8. 12) Nodifaunus: nodosus, n. sp. 2) = ee eee eA Paratype, length, 11.25 mm., young. Pe Re Te Now4922° Tortuga.
} i e tis ri di i;
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PLATE 13 (20)
12 ey razuseperuvVianuss in. Spe fe = ee ee Pe ees 83 Holotype, length, 27 mm. Pp. R. LL, No. 4959. Tortuga.
13 ahinotamidesradissan: spe 2282 es a 81 Paratype, length, 27 mm. 125 lite Jk, IN@; ZO Tortuga.
BULLETIN 111
296
EXPLANATION OF PLATE 13 (20)
Figure
ile
10.
ital,
. Tortucerithium textilis, n. sp.
. Thianassa ciconia, n.
. Trocotaulax elegans, n.
. Trocotaulax elegans, n. sp.
. Rhinotamides rudis, n. sp.
Tortucerithium textilis, n. Holotype, length, 49.5 mm. Pana lew NOs tO oie Tortuga.
Paratype, length, 32 mm. P. R. I. No. 4932: Tortuga.
. Tortucerithium textilis, n. sp. ——
Paratype, length, 41 mm. P. R. 1., No. 4933. Tortuga.
. Sympanotomus muricatus, n. sp.
Holotype, length, 30 mm. 2, Tats doy INOS SOA Tortuga.
sp. Holotype, length, 15.75 mm. PB. R. L., No, 4914: Tortuga.
. Trocotaulax elegans n. sp. ~~
Paratype, length, 15 mm. Paola eNose unis Tortuga.
sp. Paratype, length, 14.25 mm. Peekial Non 402: Tortuga.
Holotype, length, 14 mm. Pe Re I Noy 4903: Tortuga.
Holotype, length, 27 mm. Pee Ee No 496: Tortuga.
Turritella inuya, n. sp. - Holotype, length, 32 mm. P. R. I., No. 4895. Tortuga.
Turritella inuya, n. sp. Paratype, length, 17 mm. P. R. I., No. 4896. Tortuga.
Plate
2 ee ee eee 88
pees Ree ee tall)
jth ee es 80
ee ee 80
= fp)
i nay Se a ee 73
Pu, 20, VoL. 28 Buu. AMER. PALEONT. No. 111, Pu. 13
iit hiya
; ay PA
i
iy ig Aas | BN Ke nM Meh,
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140)
BULLETIN 111
EXPLANATION OF PLATE 14 (21)
Figure
298
Plate
1. Perustrombus’ wheeleri, ni sp. =... eee
. Torgnellus peruvianus, n. sp.
Holotype, length, 77 mm. Pp. R. I, No. 4939. Baculites zone.
Same specimen as last.
. Perustrombus ‘wheeleri, n: isp. 2 5 8 eee Same species, apical view, greater diameter, 40 mm. .Anchura, pacifica, ny ‘Sp. 2) = ee ee
Holotype, length, 31 mm. iPS OR. 1 No. 4943.
Baculites zone.
Holotype, length, 40 mm. 325 1h, Ie, IN@; 48240),
Tortuga.
. Perustrombus (Orthostrombus) tortugensis, n. sp.
Same specimen as last.
. Torgnellus peruvianus, n. sp.
Holotype, length, 46 mm. Pp. R. I., No. 4938. Baculites zone.
Same specimen as last.
. Perustrombus’ wheeleri, n: sp. —0-..2)202. 4 eee
94
94
. 94
. Perustrombus (Orthostrombus) tortugensis, n. sp.
92
95
95
- 93
Buu. AMER, PALEONT.
No. 111, Pu.
14
PLATE 15 (22)
12. Calyptraphorus hopkinsi Olsson _.....———-___--___ __-.. ee OG
Length, 42 mm. PASRa le Now 94.22 Baculites zone.
13. Glauconia cordalis, n. sp. ne Ae ea eee en
[3 lod
Holotype, length, 27 mm. 1ees day dies INOS ZIONS Baculites zone.
14. Parinana magma Woods —
Length, 52 mm. PeeRe le eNor 4930: Parinas sandstones, Cabo Blaneo.
Ser eee 79
142
Figure
IE
10.
IGE
~Rhombopsis meridionalisen. (Sp.
. Fasciolaria sechura, n. sp. 22-2. ee ee
+ Turritella desolata; mn: sp. 02..22..4 2 Eee
. Lyria concha, n. sp.
. Lyria concha, n. sp.
BULLETIN 111 300
EXPLANATION OF PLATE 15 (22)
Rhombopsis) meridionaliss ona sSp se Holotype, length, 25.5 mm. IPS Tits I, IN@s 40s} Tortuga.
Paratype, length, 22.75 mm. IP, lata Io, INO Zo haes Tortuga.
Holotype, length, 43.75 mm. Dee Now 49.50) Baculites zone.
Paratype, length, 33 mm. RP. R. Ds, No, 4901. Baculites zone.
> Turritella:desolata, n. sp! 2-2 Eee eee 74
Holotype, length, 31.5 mm.
Paola Now490.0:
Baculites zone.
Sto ae ee 103 Holotype, length, 17 mm.
125 IRs Me, INOS ZEYe
Tortuga.
BA Re ee a ee = 03 Paratype. length, 18 mm.
P. R. 1, No. 4958.
Tortuga.
“ Calyptraphorus hopkinsi Olsson) oa ee 96
Length, 49 mm. P. R. I., No. 4941. Baculites zone.
wlurritella.bartsias nn. sp. 222222) 2 eee W5
Holotype, length, 80 mm. P. R. I., No. 4902. Pan de Azuear. Basciolaria. “sechura, ns \Sp;, ()=32. ee ee eee 100 Paratype, length, 32 mm. RAR de Nos 4951" Baculites zone. Latirusstribulus) naispy 22 ee een) Holotype, length, 42 mm. PR. I. No: 4949: Baculites zone.
Pu. 22, Vou. 28 BULL. AMER. PALEONT. Wo: 111) Pid
PEATE 16) (2)
144 BULLETIN 111 302
EXPLANATION OF PLATE 16 (23)
Figure Plate 1. Parapachydiscus, sp. — Sie oe pee ek ES 4 107 Specimen, greater diameter, 87 mm. Pee Ly Noy 4962. Baculites zone. 2 Turritella. prelissoni; ms) sp. -..<.24.).-- = eee 73
Holotype, length, 45 mm. Pork: No: 4962: Baculites zone.
3. Baculites| lyelli«d@’Orbigny 222-02 3 ee eee OF Fragment with shell removed to show sutures. Length of piece, 48 mm.
P. R. 1. No. 4960. Baculites zone.
4.Baculites, lyelli d’Orbigny —.....\.-5...- eee eee 104 Same specimen, septal view.
. Baculites lyelli d’Orbigny Fragment, length, 150 mm,
Py Wits ey INO, GANS Baculites zone.
ou
P. R. I., No. 4963. La Mesa.
7. Paciceras gerthi, n. sp. — Same specimen as last.
eee ee
ey a need, (eh ON) ae
PLATE 17 (24)
146 BuLLETIN 111 304 EXPLANATION OF PLATE 17 (24) Figure Plate
1. Coahuilites (Austrosphenodiscus) peruviana Gerth ~~ ~~-— 110 Topotype, greater diameter, 86 mm. P. R. 1., No. 4867. La Mesa.
2. Coahuilites (Austrosphenodiscus) peruviana Gerth ~~. 110 Same specimen as last.
3. Cardium > abnormalis, ‘mn: sp: -.2 4.22. 3 eee Holotype, height, 36 mm. IP, Tite, Io, IN@, 44st Baculites zone.
4. Turrilites| peruvianus, n. ‘sp. -..--..----2 eee 107 Holotype, diameter of fragment, 351 mm. Pp. RR. L, No. 4870: Baculites zone.
5. Glossocardia (Tortucardia) stephensoni, n. sp. Tae 46 Paratype, length of hinge, 30 mm, P. R. 1., No. 4864. Tortuga.
6. Glossocardia (Tortucardia) stephensoni, n. sp. 46 Holotype, length, 31 mm. P. R. I. No., 4865. Tortuga.
7. Glossocardia (Tortucardia) stephensoni, n. sp. ~~ 46 Paratype, length, 28.5 mm. Pehle INO. 48668 Tortuga.
8. Volsella cerva, n. sp. eee Ns eee ee 37 Holotype, length, 25 mm. P. R. 1., No. 4863. Tortuga.
9) Paciceras’ pacificum;. ns Sp; 22.522 Eee bbl Holotype, greater diameter, 73 mm. P. R. L., No. 4868. La Mesa.
10. Paciceras pacificum, n. sp. Ce Ce eee eee ene eee ee!
Same specimen as last.
un id i } ig uh Cus rs
Pu. 17, Vou. 28 Buu. AMER. PALEONT. No. 111, Pu. 10
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~PALEONTOLOGICAL RESEARCH INSTITUTION IvHaca, New York U. B.A:
Notice !
This permanent record copy is printed on
all rag baper.
BULLETINS OF
AMERICAN PALEONTOLOGY
Vol. 28
ns ALS ee
No. ri2
NOTES ON EOCENE GASTROPODS, CHIEFLY CLAIBORNIAN
By
Katherine VanWinkle Palmer
April 19, 1944
PALEONTOLOGICAL RESEARCH INSTITUTION ItHaca, NEw York We tsb ve
f if (aimee mre bopaioy \ APR 27 1944
Eee ferns? ee
NODES ON EOCENE (GAS DROP ODS, CHIBbE DY CLAIBORNIAN
By
KATHERINE VAN WINKLE PALMER
INTRODUCTION
After completing my report on the Gastropoda of the Claiborn- ian? middle Eocene embayment of the southern United States, a study of the Jacksonian upper Eocene univalves of the same area was undertaken. In the prosecution of this work certain corrections, additional notes and photographs of type specimens pertaining to the earlier Eocene faunas have accumulated. Such materials would seem to be more convenient for future refer- ence if published as a unit and not interpolated in our forth- coming Jackson report.
The descriptions of several unusual species, mostly Claiborn- ian may be noted. Some of the specimens of the species de- scribed were sent to the author by the late T. H. Aldrich of Birm- ingham, Alabama. Those of one species were collected by Win- nie McGlamery of the Geological Survey of Alabama.
The writer wishes to thank Miss MceGlamery and the author- ities of the Alabama Museum of Natural History for the privi- lege of publishing the descriptions of the new species, the spec- imens of which are in the cabinets of that museum.
1 Palmer, K. Van W.: The Claibornian Scaphopoda, Gastropoda and di- branchiate Cephalopoda of the sowthern United States, Bull. Amer. Pal- eont., vol. VII, No. 32, 1937, pt. 1, 548 pp.; pt. 2, 549-730 pp., 90 pls.
4 BULLETIN 112 308
SYSTEMATIC DESCRIPTIONS
Phylum MOLLUSCA Class GASTROPODA Family TROCHIDA Genus CALLIOSTOMA Swainson, 1840 Swainson, Treatise on Malacology, 1840, p. 3551. Genotype by subsequent designation, Herrmannsen (Ind. Gen. Malae., I, 1846, p. 154), Trockus conulus Linneus—‘‘conula Mart. 166. f. 1588’? in
Swainson (fide Hanley, Ipsa Linn. Conch., 1855, p. 322). Living. Medi- terranean and Adriatic Seas; Atlantic at Canary Isls., Madeira and Azores.
Subgenus EUTROCHUS A. Adams, 1863
Adams, Proc. Zool. Soc. London, 18638, p. 506. Genotype by monotypy, H. perspectivus Adams, loc. cit. EH. adamsi Pilsbry (Man. Conch., vol. XI, 1889, p. 402). Living. Tasmania.
Calliostoma (Eutrochus) claibornianum, n. sp. Plate 2, figs. 4-6
Shell medium in size ; nucleus of about one and one-half smooth whorls, very slightly constricted between the nuclear and post- nuclear whorls. The sculpture of the postnuclear whorls be- gins gradually with three strong revolving ribs which maintain their primary strength for several whorls. Secondary spiral ribs arise and increase in strength until on the body whorl there are about five revolving ribs of equal size from the suture to the broad border of the whorl. Spiral ribs crenulated; peripheral margin of the body whorl broad, carinated above and below; finer spiral ribs are interpolated between the two margins. Basal area covered with close-set revolving ribs; umbilicus deep, nar- row; columellar area long and somewhat straight; labrum brok- en.
This species seems to be the first Ewtrochus described from the southern Eocene.
Dimensions.—Height, 6.4 mm.; greatest diameter, 6 mm. (hol- otype).
Holotype. sity, Ala.
Occurrence.—Gosport sand. Claiborne, Ala., collected by T. H. Aldrich. Species known by the holotype only.
Alabama Museum of Natural History, Univer-
o
309 CLAIBORNIAN GASTROPODS: PALMER
Family EPITONIDAE
Genus EPITONIUM Roeding in Bolten, 1798
Roeding in Bolten, Museum Boltenianum, 1798, pt. 2, p. 91.
Genotype by subsequent designation, Suter (Man. New Zealand Moll., 1913, p. 319, fide Woodring Carnegie Inst. Washington, Pub. 385, 1928, p. 394), Turbo scalaris Linneus (=S. pretiosa Lamarck). Living. Western Pacifie.
Subgenus CRISPOSCALA de Boury, 1886
De Boury, Mon. Sealide vivantes et fossiles, Pt. 1; Crisposeala, fase. I, 1886, Paris.
Genotype by original designation, ‘‘C. (Scalaria) crispa’’ (aamarck), op. cit., p. 1, pl. 1, figs. 1-5. Eocene. Paris Basin.
Epitonium (Crisposcala) failianum, n. sp. Plater 2; hess O. 010
Shell medium in size; spire not complete; whorls rounded; sculpture of curved longitudinal lamellae which have well-devel- oped spines below the suture; about 18 such cost on the body and penultimate whorls; whorls with incipient or what might be obsolete spiral ribs; the whole surface of the whorls between the lamellz covered with microscopic revolving striz; basal cord incipient, seen only with the binoculars; base of lameilz back of the columellar and apertural margins united into a flare with a slight concavity before the callus ; aperture auriculate.
This species differs from the known Claibornian and Jack- sonian species of Epitonium in the absence of a well-developed basal cord, the presence of the flare in the umbilical region and in having finer spinous scalariform lamelle.
The form is described from the holotype only.
Dimensions.—Height, 12 mm. (incomplete) ; greatest diameter, 7 mm. (holotype).
Holotype-—Alabama Museum of Natural History, University, Ala.
Occurrence.—Jacksonian or Claibornian. “One and one-half miles east of Fail, Alabama, in marl bed, just under prairie rock and above clays.”
6 BULLETIN 112 310
Subgenus GYRGSCALA de Boury, 1910
De Boury, J. Conchyliol., vol. 58, 1910, p. 228. Genotype by original designation (loc. cit., pi. XI, fig. 1) Scalaria com- mutata Monterosato. Living. Mediterranean.
Epitonium (Gyroseala) meglameria, n. sp. Plate 2, figs. 11-13
Shell large; whoris rounded; apical whorls broken and worn; the immediate surface of the whorls between the lamellz smooth ; sculpture consists of large, projecting lamellae continuous from whorl to whorl because of the fused overlap of each lamella at the suture; varices irregular; basal cord conspicuous; labrum thickened; slight concavity below the columellar area; auricle fairly well developed.
This species differs from the other species of Epitonium in the southern Eocene by the presence of the thinner projecting lamellie and by the smoothness of the surface of the shell between the lamellee.
Dimensions.—Greatest diamenter, 14.5 mm. (largest speci- men), Specimens not complete.
Syntypes.—Alabama Museum of Natural History, University, Alabama.
Occurrence.—Lower Claiborne. Lisbon formation,? two miles south of Gilbertown, highway 29, Choctaw County, Alabama, collected by Winnie McGlamery, June 10, 1936.
Family HIPPONICIDE Genus HIPPONIX Defrance, 1819
Defranece, J. Chim. Hist. nat., t. 88, 1819, p. 217, figs. 1, a-f.
Genotype by subsequent designation, Gray (Proe. Zool. Soe. London, pt. XV, 1847, p. 157), Patella cornucopia Lamarck. Eocene, Paris Basin. Hipponix vagus, n. sp. Plate 2, figs. 1-3
Shell large, aperture round, apical end constricted, forming a beaklike prominence; horseshoe-shaped muscular scars well de- veloped; surface covered with moderately coarse radiating strie. The type is worn but the radiating ribs are plainer than they appear in the photograph.
The species is known from a large unique specimen, the size
2 Applied because it is used in commen nomenclature but according to
Lexicon of Geologic Names, Bull. U. S. G. S., No. 896, p. 1189, the name for the Eocene formation is preoccupied by usage in the Paleozoic.
311 CLAIBORNIAN GASTROPODS: PALMER 7
of which is extraordinary for a southern American Hipponix, about four times the size of the largest specimens of H. pyg- meus found in the Gosport sand. H. vagus equals in size in- dividuals of the genotype in the Paris Basin Eocene. There is such a large gap between the common size of tiny H. pygmeus and this shell that it does not seem that the present specimen could even be a gerontic individual of H. pygimeius.
H. sylverupis Harris (Bull. Amer. Paleont., vol. III, No. 11, 1899, p. 83, pl. 11, fig.10, a) of the Sabine (Wilcox) Eocene is about twice the size of H. pygmeus but about half the dimen- sions of H. vagus.
Dimensions.—Height, 10 mm. (from apex to margin of shell beneath) ; 22 mm., greatest diameter.
Holotype —Alabama Museum of Natural History, University, Ala.
Occurrence.—Gosport sand. Claiborne, Ala., collected by T.
H. Aldrich.
Family THIARIDA (MELANIDA:) Genus FHIARA Roeding in Bolten, 1798
(Melania Lamarck, 1799)
Roeding in Bolten, Museum Boltenianum, pt. 2, 1798, p. 109.
Genotype by monotypy4 Helix amarula Linneus. The same by subse- quent designation, Herrmannsen (Ind. Gen. Malac., II, 1849, p. 576 Tiara emend.) Living. Madagasear, Comoros, Mauritius and Réunion.
Thiara aldrichi, n. sp Plate 2, figs. 7, 8
Shell medium size; thin; apex broken; on the lower part of the whorls are coarse spiral ribs which decrease in size toward the body whorl; the whole surface of the shell is covered with microscopic striations which are most conspicuous over the basal
3 The specimen, 8.5 mm., greatest diameter, mentioned in the Claiborne report (Palmer, 1937, p. 149) is, on additional examination, found to be probably a broken individual of Calyptrea aperta (Solander). The rem- nant is a ring of the lower margin of a shell, the middle and apical areas have been destreyed. A spiral line is preserved which suggests that the specimen is more likely Calyptrea than Hipponia.
4 Remaining species mentioned by Bolten are nomina nuda fide Pilsbry and Bequaert (Amer. Mus. Nat. Hist., Bull. 53, 1927, p. 250).
8 BULLETIN 112 312
part of the body whorl; whorls with to to 12 tuberculous longi- tudinal folds which extend from above the middle line downward and are less sharply developed on the body whorl; aperture en- tire; callus thin. There are a few brownish spots and splashes of coloration preserved.
This species is unusual in the southern Eocene. It represents a fresh-water species accidentally brought into a typically marine fauna.
The form resembles somewhat the general appearance in sculpture of T. scabra (Miller) (Martin, Foss. v. Java, Bd. 1, 1905, pl. 36, figs. 572-573) of the East Indies, the species which has been used by authors as the type of Plotia Roeding in Bolten’. The Claiborne species is not, however, applicable within the lim- its of the valid genotype of the subgenus. The figures of Melania qwinteri von dem Busch in Reeve, Icon. Conch., Melania, 1860, pl. XXII, fig. 157, suggest also the characters of this shell.
Dimensions.—Height, 17.3 mm.; greatest diameter, 8.1 mm. (holotype).
Holotype-—Alabama Museum of Natural History, Universi- ty, Ala:
Occurrence.—Gosport sand. Claiborne, Ala., collected by T. He Aldrich:
Family ARCHITECTONICID4&
Genus ARCHITECTONICA Roeding in Bolten Roeding in Bolten, Museum Boltenianum, 1798, pt. 2, p. 78. Genotype by subsequent designation, Gray (Proe. Zool. Soc. London, pt. XV, 1847, p. 151, ‘‘ Architectoma’’), Trochus perspectivus Linneeus. Liv- ing. Indo-Pacific.
Subgenus GRANOSOLARIUM Sacco, 1892 (Non Solariazis Dell, December, 1892, Trans. Wagner Free Inst. Sci., vol. ITT, pt. II, pp. 323, 324, genotype S. elaboratum Conrad.) Saeco, Boll. Mus. Zool. Anat. comp., vol. VII, April, 1892, p. 56; I Mol- luschi dei Terreni terziarii del Piemonte e della Liguria, pt. XII, June, 1892, p. 59.
5 Roeding in Bolten, op. cit., p. 95, did not list 7. seabra [=T. spinu- losa (Lamarck, 1882)] or its equivalent. Pilsbry and Bequaert, Nautilus, vol. 37, No. 1, 1923, p. 36, designated Plotia lineata [Bolten] as the gen- otype.
313 CLAIBORNIAN GASTROPODS: PALMER 9
Genotype by original designation, Solarium millegranum Lamarck (Ann. s. Vert., VII, 1822, p. 6). Miocene, Pliocene. Italy. Sacco, June, 1892, OnNcii-. plaid fies 18?
If one follows Dall (1892) and Cossmann (Essais Paléoconch. comparée, Io liv., 1915, p. 169), as I did in 1937, in uniting A. elaborata (Conrad) and A. ornata (Lea), then Granosolarium Sacco and Solariaxis Dall are synonymous. Granosolarium has priority.
However, observing the continuation of the Claibornian stocks of Architectonicas into the Jackson Eocene, one feels that 4. elaborata and A. ornata do belong to two different types of shell, even though they may be related and there are troublesome var- iations in the Lower Claiborne. Consequently Dall’s name and that of Sacco may stand for separate subgenera.
A. canaliculata (Lamarck) (Ann. Mus. nat. Hist. nat., Paris, t. 4, 1804, p. 53) represents the subgenus in the Paris Basin and English Eocene.
A, elaborata and A. acuta are representatives of Solariaxis in the southern Eocene.
Architectonica (Granosolarium) ornata (Lea)
Solarium ornatum Lea, 1833, Cont. Geol.. p. 120, pl. 4, fig. 108; H. C. Lea, 1848, Acad. Nat. Sei. Philadelphia, Proc., vol. 4, p. 106; d’Orbigny, 1850, Prodrome de Paléontologie, vol. 2, p. 348; Heilprin, 1879, Acad. Nat. Sci. Philadelphia, Proc., vol. 31, p. 224; de Gregorio, 1890, Ann. de Géol. et Paléont., 7 liv., p. 136, pl. 12, figs. 53 a, b; Harris, 1895, Bull. Amer. Paleont., vol. 1, No. 1, p. 31. non S. ornatum Sowerby in Fitten, 1836, Trans. Gecl. Soc. London, ser. 2, [V, App. p. 336.
Solarium canaliculatum Conrad, 1834, Appendix to Morton, Synopsis Org. Remains Cret. Group, p. 3 non S. canaliculatum Lamarck, 1804, Ann. Mus. nat. Hist. nat., t. 4, p. 53.
Architectonica ornata (Lea), Conrad, 1865, Amer. Jour. Coneh., vol. 1 p. 30; Conrad, 1866, Smith. Mise. Cell., vol. VII, No. 200, p. 13.
Solarium elaboratum ornatwm (Lea), Dall, 1892, Trans. Wagner Free Inst. Sci., vol. IIL, pt. Il, p. 324 section Solariazis.
Solarium elaboratum Conrad, Cossmann, 1893, Ann. Géol. et Paléont., 12 live, P= 2d.
Solarium (Solariaxis) elaboratum Conrad, Cossmann, 1915, Essais de Paléoconch. comparée, 10 liv., p. 169 partim, pl. VII, figs, 19, 20 non 18.
Architectonica elaborata (Conrad), Palmer, 1937, Bull. Amer. Paleont., vol. VII, No, 32, p. 164 partim, pl. 18, figs. 15, 16, 19; pl. 81, figs. 9-11 section Granosolarium.
)
Shell convex above, flattened below, furnished with many granular transverse lines, three of which, on the superior part of the whorl, are larger than the others, furrowed on both sides of the carina which is
10 BuuurtTin 112 314
erenulate, longitudinally striate; substance of the shell rather thick; su- ture furrowed; umbilicus very wide, perspective, beautifully crenate at the edge, furrowed within and longitudinally striate; whorls six; mouth suborbicular.
Length. 2, Breadth 9-20ths, of an inch.
Observations. This species is very like Brander’s figure of Turbo can- aliculatum, and Sowerby’s figure of the same species, Solartwm canalicu- latum, plate 524. On comparison, however, with a specimen from Hamp- shire, sent to me under that name, I find them very different; the umbilicus being much wider in the species from Claiborne, which is also more ear- inate, and has smaller and more numerous granulate lines.—[Lea, 1833.]
The ornamentation pattern of the adult is based on a tripri- mary plan. On the young or postnuclear whorls the whorl is bicarinate. On the adult there is one pronounced nodose spiral rib or primary just below the suture and another just above the suture. Between the upper and middle primaries there are two or three finer nodose secondary lines with diminutive tertiary threads. The interspace between the middle primary and the basal carina is prominently excavated. The dorsal and ventral surfaces are conspicuously covered with longitudinal coarse striations. The base is convex and covered with five or six (not including the peripheral carina) nodose revolving ribs with finer intercostal lines, varying in coarseness away from the umbilical margin.
In photographs of the ventral surface, the convexity of the shell hides the excavation of the area just in front of the marginal carina. The ventral surface therefore takes on an appearance more like A. elaborata (Conrad) which is deceiving. Lea’s orig- inal figure of the ventral surface probably does not show the true character of the ventral margin. The Meyer drawing of type material produces a flatter perspective of the ventral surface and hence shows more of the excavated area. Otherwise Lea’s fig- ure and the Meyer drawing de not seem to represent the same species. Comparing the Meyer drawings (Palmer, 1937, pl. 81, figs. I, 11) of A. meekana and A. ornata, one can see the close relationship between the two species.
In respect to the coarse radiating strie A. ornata exhibits a relationship more with A. meekana than with A. elaborata. A. ornata differs from A. elaborata in having a convex base, as well as having a furrowed area above the peripheral carina. The
315 CLAIBORNIAN GASTROPODS: PALMER TT
major difference between the two Gosport sand species is the adult triprimary pattern of revolving ribs of A. orneta which A. elaborata lacks. This difference in the sculpture places each of the two species in a different subgenus.
Dall thought of A. ornata as a variety of A. elaborata (Con- rad). In 1937, I decided that A. ovnata might be the young of A. elabovata and so followed Dall in grouping the two species. Be- cause of such a union, 4. elaborata was included in that group of Architectonica which is typified by A. millegrana (Lamarck) of the Miocene and Pliocene of Europe and represented by A. can- aliculata (Lamarck) of the Eocene of the Paris Basin and Eng- land. The group is well developed in the southern Eocene. To this subgenus A. ornata belongs. The first clue to such a rela- tionship is in the comparisons of Lea, Conrad and Heilprin of A. ornata with A. canaliculata (Lamarck). The sculpture of A. oynata is close-set and it is in this fact that the species has been probably correlated with A. elaborata. It is in some of the va- rities of 4. meekana where the margin is more acute and flaring and the intermediate revolving ribs are more subdued that the triprimary pattern of sculpture is most conspicuous and most easily observed.
A. ornata is fairly well represented in the Gosport sand. As far as collections which I have studied are concerned, the shells of A. orneta are smaller than A. elaborata. One specimen in our collection from the Lower Claiborne, Cook Mountain formation, at Big Branch of Cedar Creek, NW of Stone City, Texas, is very much like typical A. ornata. In the Jackson the species is developed in a varietal stage.
Dimensions.—Height, 7.7 mm.; greatest diameter, I3 mm. (largest specimen).
Lectotype—No. 5600 (not 5500 as given in 1937), Academy of Natural Sciences, Philadelphia, Pa.
Occurrence—Lower Claiborne. Cook Mountain formation, loc. 766, “Big Branch of Cedar Creek, east of Mr. Pollard’s (de- ceased) farm, three miles NW of Stone City, Burleson County, Texas,” collected by J. W. Wells; Gosport sand. Claiborne, Ala.
(type).
112 BULLETIN 112 316
Architectonica (Granosolarium) meekana Gabb Plate 1, figs. 4-7
Architectonica meekana Gabb, 1860, Acad. Nat. Sci. Philadelphia, Jour., 2d ser., vol. IV, p. 385, pl. 67, fig. 40; Conrad, 1865, Amer. Jour. Conch., vol. 1, p. 30; Conrad, 1866, Smith. Mise. Coll., vol. VII, No. 200, p. is
Solarium Meekanum (Gabb), Heilprin, 1891, Acad. Nat. Sei. Philadel- phia, Proc. for 1890, vol. 42, p. 400.
Solarium acuium Meckianum (Gabb), Dall, 1892, Trans. Wagner Free Inst. Sei., vol. ITT, pt. II, p. 324 under section Solariazis.
Architectonica acuia meekiana Gabb, Palmer, 1937, Bull. Amer. Paleont., vol. VII, No. 32, p. 168 partim, pl. 81, figs. 1, 2; non pl. 20, figs. 9, 11, 13. Section Granosolarium.
Diseoid, whorls five, strongly carinate on the edge and somewhat round- ed below; mouth subrhomboidal; umbilicus wide; surface above marked on the edge and on the middie of the whorl hy two large, revolving nodose lines, and on the rest of the top by five smaller ones; between the two large ones there are numerous cross lines passing from one to the other; be- low, besides the ‘‘keel’’ on the edge of the whorl, there are seven ribs, one large one bordering the umbilicus and six smaller alternating ribs; in the umbilieus there is one rib on the middle of the whorl, besides the one on the edge.
Dimensions—Height .1 in., diameter of the dise .32 in., width of umbili- eus .15 in,
This beautiful species, under a glass, looks as if covered with ‘‘ bead- ing’’, all the ribs having that peculiar structure. Four specimens from Caldwell Co., in my collection. One very fine one from Wheelock, in the collection of the Smithsonian Institution—[Gabb, 1860.]
Dall in 1890 included A. meekana under A. acuta Conrad, Jackson Eocene species. The original figures of 4. meekana a A. acuta are poor. In 1937 in the Claibornian gastropod report, I followed Dall in grouping 4. meckana and A. acuta. In study- ing the oe ee gastropods one becomes aware that that which I called A. acuta in 1937 does not display the characters of the Jackson es
Through the courtesy of the Academy of Natural Science at Philadelphia, photographs of the types of A. acuta and A. meek- ana were supplied. The illustrations of A. acuta will be included in the forthcoming paper on the Jackson fauna and those of 4. meekana are reproduced herein, he present type material of A. meekana consists of two small specimens which are still not adequate to give a complete impression of the typical species. Without topotype material it is impossible to explain the exact characters of the species, sensu stricto, and hence it is prema-
317 CLAIBORNIAN GASTROPODS: PALMER 13
ture to define the variations from type which the species may ex- hibit. But it is worthwhile to place on record additional pictures of the type material. The Meyer drawing of a specimen in the Gabb collection from Wheelock, Texas which Meyer compared with the type is very well drawn and shows the details of the sculpture better than the photographs. The specimen is small (Palmer,.1937, pl. Si, fig. 1).
Suffice it to say that that which I illustrated in 1937 as A. acuta is not the true A. acuta. The true A. acuta is a Jackson species and belongs to the 4. elaborata (Gosport sand) stock which is of a different subgeneric development than A. meekana. The A. acuta of 1937 is named A. meekana splendida in this
paper.
The specimen figured in 1937, pl. 20, figs. 9, 11, 13 as “A. acuta meekiana’ is not A. meekana Gabb. The specimen is from the Lower Claiborne (Weches formation) at Smithville, Texas. It was from an early Texas collection and labelled “S. acutum var. meekanum”’. ‘The specimen actually represents a member of the A. elaborata stock and may be nearest to A. vespertina Gabb. Since the sofar available figures of A. vespertina are too poor to identify A. vespertina Gabb (Acad. Nat. Sci., Philadelphia, Jour., 2d ser., vol. IV, 1860, p. 384, pl. 67, fig. 39; Palmer, 1937, pl. 82, figs. 2, 4) further naming is left until topotype material is identified.
A. meekana and its variations represent an important stock in the Lower Claiborne-Jackson beds. The predominate character of the stock is the presence in the adult of the three major revolv- ing ribs—one on the edge of each margin of the whorl and one about the midline. Between the three large revolving ribs are finer spiral lines and the whole spiral sculpture is crossed by fine conspicuous radiating bifurcating threads. The spiral ribs are pronouncedly beaded. The minor threads vary on specimens from different localities. The earlier postnuclear whorls are bi- carinate. :
Dall’s A. textiina (Trans. Wagner Free Inst. Sci., vol. III,
14 BULLETIN 112 318
pt. II, 1892, p. 328, pl. 22, figs. 1, 2, 3) from Wautubbee, Miss- issippi, Lower Claiborne, appears to be of this line. The basal sculpture according to the illustration varies considerably from the typical 4. meekana. A. ornata Lea of the Gosport sand (not A. elaborata) belongs to the A. megekana stock instead of to the A. elaborata group. At certain Lower Claiborne localities, such as Hammett’s Branch, Louisiana and Hickory, Mississippi, the surface of the shells of the A. meckana stock tends to be smooth- er than typical and many of the spiral ribs are not present. Spec- imens from a locality about “2 miles northeast of Newton, Miss- issippi” have the very fine revolving ribs and an acute margin.
Syntypes.—No. 13291 (two specimens), Academy of Natural Sciences, Philadelphia, Pa.
Occurrence.—Lower Claiborne. Stone City formation (Cook Mountain), Caldwell “Co.” Texas (type).®
Awrehitectenica (Granesolarium) meelkana splendida, n. var.
Architectonica acuta Palmer, 1937, Bull. Amer. Paleont., vol. VII, No. 32, p. 167 partim, pl. 20, figs. 12, 14-17.
Neon Architectonica acuta Conrad, 1854, in Wailes, Rept. Agr. and Geol. Mississippi, p. 289, pl. 17, figs. la, 1b; Conrad 1855, Acad. Nat. Sei.
Philadelphia, Proc., vol. 7, p. 261. Reprint 1939, Bull. Amer. Paleent.,
)
voi.. XMIV, No. 86, pp. 7, 19, pl. 4, figs. La, 1b:
The details of the young and adult stages of this form are il- lustrated in the 1937 Claiborne bulletin where the species was confused with A. acuta Conrad.
On the earlier postnuclear whor!s, the two posterior crenulated carine predominate exhibiting a bicarinate appearance of the whorl. The area below the anterior nodose carina to the suture
6 The word ‘‘Co.’’ is probably a misstatement and means ‘‘town of Caldwell’’ (Roemer, Amer. Jour. Sei., 2d ser. vol. VI, 1848, p. 23). For map of the Caldwell-Wheelock area see Renick and Stenzel. Univ. Texas Bull., No. 3101, 1931, p. 75. Stenzel and Turner (Type Invertebrate Fos- sils of North America, Eocene Gastropoda 57, eard No. 85) suggested that the type loeality of Turriteila naswia Gabb, described in the same work with A. meekana from Caldwell ‘‘Co.’’ and Wheelock, Texas, probably is ‘“Stone City (Moseley’s Ferry), bluff on right bank of Brazos River at bridge of State highway 21 and bridge of Southern Pacifie Railroad, Bur- ieson County, Texas.’’
319 CLAIBORNIAN GASTROPODS: PALMER 15
is deeply excavated. Shortly the excavated area enlarges and the fine crenulated spiral rib just above the suture becomes conspicu- ous, developing the characteristic sculpture which consists pre- eminently of three large nodose spiral ribs—one above the suture, one below the suture and one in about the midline of the whorl. This pattern is the motif of the decoration of dA. meekana Gabb of the Lower Claiborne as well as of A. ornata (Lea) of the Gos- port sand. The stock is also present in the Jackson Eocene.
This particular variety differs frem typical 4. meekana in the greater acuteness of the periphery. That area as it spreads may contain several fine spiral threads between the peripheral and middle carinze or the spiral strie may be lacking. The ventral margin is also more extended with a wide space between the peripheral margin and the previous spiral rib which rises above like a shelf. The whcle surface of the shell is delicately covered with divaricating radiating lines. This is a feature characteristic of the species.
The variety was abundantly developed at Lapiniere Landing on the Ouachita River, Louisiana where the shells are exquisitely adorned like filigree.
Dimensions.—Height, 6 mm. ; greatest diameter, 15 mm. (holo- type).
Types.—Holotype, No. 2856; paratype, No. 2854; figured specimen, No, 2855, Paleontological Research Institution.
Occurrence.—Lower Claiborne. Cook Mountain formation. loc. 725, Sabine River, Texas side, opposite SW corner of SE i4ssec./35, 0. 5.N., R 13 W., field No. 21 (A.C. Veateh, Geol. Sur. La., Rept. for 1902, No. 3, p. 129, map pl. XX XIII), (type) ; loc. 724, Columbus, Sabine Parish, La. (A. C. Veatch, op. cit., p. 130, map XXXIII); loc. 741, east bank of the Ouachita River, Lapiniére Landing, Ouachita Parish, La. (A. C. Veatch, op. cit., No, 4, pp. 155, 160, map pl. XX XVIII).
Architectonica (Granosolarium) texcarolina, n. sp. Plate 1, figs. 8-11.
Shell small; the whole surface of the shell covered with beaded spiral ribs. Beginning with the first postnuclear whorl and contin- uing for about two whorls the sculptural pattern consists of two
16 BuLLeTIN 112 320
primary nodose ribs with two secondary nodose ribs between. The upper rib is just below the suture and slightly overhangs it. The lower rib is above the suture with a fine spiral nodose rib between the primary rib and the suture. Between the two large ridges are two smaller nodose revelving ribs. On the later whorls a third primary nodose revolving rib develops which eventually becomes the peripheral carinate margin and it, together with the first two primary ribs, form the triprimary pattern of the sculp- ture of the mature shells. On the later whorls, tertiary nodose lines appear in the area between the upper primary ribs. A sec- ondary rib is interpolated between the peripheral rib and the primary above. The sutures are impressed. The umbilical bor- der and adjoining rib are enlarged. Three more smaller ribs with a finer rib cover the basal area between the periphery and the last secondary spiral. All are sharply nodose.
These shells described as new were included by me in 1937 under A. elaborata, var. because of the fact that A. ornata was not at that time separated from A. elaborata. This species differs from A. elaborata in the fundamental pattern of the sculpture, that of biprimary spirals on the young whorls with a triprimary pattern in the adult. Such sculpture is the major pattern of A. ornata of the Gosport sand and A, meekana of the Lower Clai- borne. A. texcarolina differs from both A. ornata and A. meek- ana in having coarser ribs with the ribs closer together. The ra- diating, divaricating threads are conspicuous in A. ornaia and A. meekana while in A. texcarolina the radiating lines have dissect- ed the spiral ribs into coarser beads and hence have obscured themselves. The basal sculpture consists of about the same num- ber of spirals in the three species. The secondary ribs are less conspicuous in A. texcavolina than in A. ornata and the spirals are more coarsely beaded and the umbilical ribs are larger in the for- mer.
There is in the Gosport sand a variation of A. ornata which has coarser spiral ribs more tightly set than typical and some- what as in A. texcarolina, but they are more subdued and the revolving ribs on the ventral surface are finer and more numer- cus than in both typical A. ornata and A. texcarolina.
321 CLAIBORNIAN GASTROPODS: PALMER 17
The species is described from small, probably young specimens but since the shells from two widely separated localities exhibit similar characters which differ from immature individuals of known species, it seems as though they may represent a distinct species.
Dimensions.—Height, 2.3 mm.; greatest diameter, 5 mm. (holotype).
Types.—Holotype, No. 4457; paratype, No. 4456, Paleontolo- gical Research Institution,
Occurrence.—Lower Claiborne. Crockett formation (Cook Mountain), loc. 727, Little Brazos River, Brazos County, Texas,” collected by J. E. Adams (type). McBean formation, loc. 136, Orangeburg District, Orangeburg, S. C., collected by T. A. Caine and A, C, Veatch.
Architectonica sabinia, n. n. Solarium delphinuloides Heilprim, 1880, Acad. Nat. Sci., Philadelphia, Proc., vol. 32, p. 375, pl. 20, fig. 13. Non Solarium delphinuloides d’Orbigny, 1845, in Sagra, Hist. fis. pol. y nat. Cuba, t. V, p. 189. Non Solarium delphinuloides Meyer, 1887, Ber. senckenb. naturf. Ges., p. 4.
This form requires a new name since its original name is pre- occupied by that of the Recent West Indian species of Architec- tonica described by D’Orbigny and also by that of a Jackson EKo- cene gastropod so named by Meyer.
Family TURRITELLIDA Genus TURRITELLA Lamarck
Lamarek, Mem. Soc. Hist. nat. Paris, 1799, p. 74.
Genotype by monotypy, Turbo terebra Linneus (Syst. Nat., 1758, p. 766). Living. Western Pacific. Turritella rina Palmer Plate 1, figs. 12-16
Turritella rina Palmer, 1937, Bull. Amer. Paleont., vol. VII, No. 382, p. 192, pl. 22, figs. 3, 4, 9; Bowles, 1939, Jour. Paleont., vol. 13, No. 3, p. 277, pl. 31, fig. 17; Stenzel and Turner, (1942), Type Invertebrate Fossils of North America, Eocene, Gastropoda 70, card No. 98.
Turritella wechesensis Bowles, 1939, op. cit., p. 281, pl. 31, figs. 8, 14; Stenzel and Turner, (1942), op. cit., card No. 108.
7 The description (1937) of the locality was given as that of the orig- inal collector. This has been corrected by Stenzel (Univ. Texas Pub., No. 3945, 1940, p. 854, footnote) to that of Bur. He. Geol. Texas loc. No. 21-T-1.
18 BouLLetin 112 322
The present occasion is taken to illustrate what some pro- nouncedly sculptured species can do in the matter of obliteration of that sculpture. Typical 7. rina on the adult whorls has a strong overhanging are bicarinate, the spiral iines may be beaded. Turritella wech-
carination of the whorls. The younger whorls
esensis Bowles was described as “differing from any of the other species [Turritella] of the Gulf Eocene in the obliteration of the sculpture on the adult whorls.” It was compared with 7. rina but was distinguished from that species by “the ultimate extinc- tion of the carina and the disappearance of the secondary rib- bing” in 7. wechesensis.
T. rina is a prolific Lower Claiborne species and exhibits con- siderable variation. This can probably be illustrated best by fig- ures of specimens from one locality. Those figures herein in- cluded are from Lapiniére Landing®, on the Ouachita River, Ouachita Parish, Louisiana, Cook Mountain formation (where the species was abundant) and well illustrate the potentiality ot the species. Many more from the same locality could be added to show intermediate stages between those specimens which are illus- trated. Here one sees that T. rina develops into a form with a smooth shell with the connecting stages present. Therefore a distinction between 7. viva and species which are like it except that in them the sculpture may become obliterated does not seem adequate to separate the forms. The connection of the two species mentioned is worth considering.
Family STROMBIDZE Genus ECTINCCHILUS Cossmann, 1889
Cossmann, Ann. Soc. roy. malac. Belg., t. XXIV, 4th ser., t. IV, 1889, p. 87. Genotype by original designation, Strombus canalis Lamarck. Hoecene. Paris Basin. Ectinochilus texanum cherokense, n. n. Rimella texana var. plana Harris, 1895, Acad. Nat. Sei. Philadelphia, Proe., vol. 47, p. 78, pl. 9, fig. 2. Ectinochilus texanus planws (H: uris) , Palmer, 1937, Bull. Amer. Paleont., vol. VII, No. 32, p. 246, pl. 33, fig. 4. Non kostellaria plana Beyrich, 1854, Zeit. deutsch. geol. Gesell., vol. 6, p:, 489; pl. 14) figs. 79, 9a—Ectinochilus planwn (Beyrich), Wrigley, 1938, Proc. Malacol. Soc. London, vol. 23, pt. II, p. 69, figs. 21, 22.
8 Veatch, A. C.: Rept. Geol. Louisiana, Pt. VI, No. 4, 1902, pp. 155, 160, map XXXVIII.
323 CLAIBORNIAN GASTROPODS: PALMER 19
The name of the Lower Claiborne Texan stromboid species be- comes preoccupied by that for a species in the Oligocene and Eocene of Europe.
Family CANCELLARIIDA Genus COPTOSTOMA Cossmann, 1899
Cossmann, Essais Paléoconch. comparée, 3 liv., 1899, p. 34, as a section.
Genotype by original designation, Cancellaria quadrata Sowerby. Barton Eocene. England. Wrigley, Proc. Malacol. Soe. London, vol. XXI, pt. VI, 1935, p. 357, pl. 32, fig. 1; pl. 35, fig. 46. ‘ Coptostoma rameum, n. sp. Plate 1, fig. 3
Bonellitia ulmula Palmer, 1937, Bull. Amer. Paleont., vol. VII, No. 22, p. 455, partim pl. 70, figs. 1, 7 non 8.
Non Cancellaria ulmula Harris, 1895, Acad. Nat. Sei. Philadelphia, Proce., vol. 47, p. 66, pl. 6, fig. 6. See Bonellitia ulmula (Harris), Palmer, 1937, loc. cit., pl. 70, fig. 8.
Nuclear whorls large, tilted slightly to the axis of the spire; first nuclear whorl broken, last and next to the last with sharp longitudinal ribs extending the length of the whorl; nuclear and postnuclear whorls sharply demarcated; postnuclear whorls sculptured with about six primary spiral ribs with finer interme- diate threads. There may be tertiary spiral lines over the body whorl. Well-developed longitudinal folds extend over the whorls of the spire and over the posterior area of the body whorl; two large columellar plications with a suggestion of a third; labrum coarsely denticulate ; whorls rounded.
In 1937, I included under Bonellitia ulmula (Harris), [Cop- tostoma ulmulum] a specimen from Moseley’s Ferry, Texas, which differs from C. ulmulum in the character of the protoconch, in the greater strength of the longitudinal folds over the whorls and in the presence of interstitial spiral ribs. Slight longitudinal folds occur on C. ulmulum.
It seemed when studying the Claibornian fauna that the Mose- ley’s Ferry specimen might be grouped under the possible varia- tion of the species. After finding in the Jackson Eocene the ex- istence of C. ulmulum in which the shells exhibit less divergence from the typical species than that of the specimens in the Lower Claiborne, I am differentiating the Moseley’s Ferry form speci- fically. Several specimens from a Lower Claiborne locality in Louisiana, the exact description of which has been lost, have the
20 BULLETIN 112 324
same characters as on the individual from Moseley’s Ferry, Texas. Such similarity would indicate that the specific characters were fairly constant.
Dimensions.—Height, 10.5 mm.; greatest diameter, 6 mm. (type).
Holotype.—No, 3307, Paleontological Research Institution.
Occurrence.—Lower Claiborne. Stone City formation (Cook Mountain), loc. 723, Moseley’s Ferry, Brazos River, Burleson County, Texas (type). Cook Mountain formation, loc. 138, Louis- iana,
Family SCAPHANDRIDAL
Genus ABDEROSPIRA Dall, 1896
Dall, Proc. U. S. Nat. Mus., vol. 18, 1896, p. 32.
Genotype by original designation, Bullina (Abderospira) chipolana Dall (loc. cit.; Trans. Wagner Free Inst. Sci., vol. III, pt. 6, 1903, pl. 59, fig. 23). Chipola Miocene. Florida.
Abderospira Aldrichi (Langdon) Plate 1, figs! 1, 2
Bulla (Haminea) Aldrichi Langdon, 1886, Amer. Jour. Sci., 3d_ser.,
vol. XXXI, No. 183, pp. 208, 209.
For complete synonymy, copy of the original description and additional notes see Palmer, 1937, Bull. Amer. Paleont., vol. VII, INO: 32, p)485, pl. 75, Hes. 10, 11.
Through the courtesy of J. T. Singewald, Jr., Chairman of the Geological Department at the Johns Hopkins University, the type of Langdon’s species has been loaned and photographs of the shell are included herein.
The Lower Claiborne, Lisbon formation specimen from near Newton, Mississippi, figured in 1937 has spiral lines with nar- rower interspaces and finer punctations than that of the type. Two specimens from Gopher Hill, Alabama represent, respect- ively, a mature and young shell. The larger has the spiral lines with interspaces equivalent to those of the type and the puncta- tions are similar in size. The smaller specimen has interspaces and punctations finer than the Newton shell. Therefore it seems that the difference in the size of the interspaces between the spiral lines and size of the punctations may vary considerably with the age of the individuals. At least there are yet too few specimens
325 CLAIBORNIAN GASTROPODS: PALMER 21
available to make specific distinctions on such differences of char- acter.
Holotype.—Geology Department, The Johns Hopkins Univer- sity, Baltimore, Md.
Occurrence.—Lower Claiborne. Lisbon formation, loc. 726 (see Palmer, 1937, p. 10); “Ferruginous sand” bed, 8 ft. above Gosport sand. Claiborne, Ala. (see Palmer, 1937, p. 486) (type). Loc. 1057, St. Stephen’s, Gopher Hill, at water’s edge, Washing- ton County, Ala., collected by G. D. Harris, Oct. 3, 1940.
es Rea ORB?
Adams, Arthur 1863. Description of a new genus and of twelve new species of mollusca. Proce. Zool. Soe. London, pp. 506-509. Beyrich, Ernst 1854. Die Conchylien des norddeutschen Tertidrgebirges Zeit. deutsch. geol. gesell., Bd. 6, pp. 408-500. Bowles, Edgar Oliver 1939. Eocene and Paleocene Turritellide of the Atlantic and Gulf Coast- al Plain of North America. Jour. Paleont., vol. 13, No. 3, pp. 267-336, pls. 31-34. Conrad, Timothy Abbott 1834. Catalogue of the fossil shells of the Tertiary formations of the United States ... in Appendix, pp. 1-8, to Dr. 8S. G. Morton’s Syn- opsis of the organic remains of the Cretaceous group of the United States. 1865. Catalogue of the Eocene and Oligocene testacea of the United States. Amer. Jour. Conch., vol. 1, No. 1, pp. 1-35, 191, 192. 1866. Check list of the invertebrate fossils of North America. Eocene and Oligocene. Smith. Mise. Coll., vol. VII, No. 200, 41 pp. Cossmann, Alexandre Edeuard Maurice 1893. Notes complémentaires sur la fauna Eocénique de 1’ Alabama, Ann. de. Géol. et Paléont., 12 liv., 52 pp. 2 pls. Dall, William Healey 1892. Contributions to the Tertiary fauna of Florida, with especial refer- ence to the Miocene silex-beds of Tampa and the Pliocene beds of the Caloosahatchie River. Trans. Wagner Free Inst. Sci., Philadelphia, vol. 3, pt. II, pp. 201-473, pls. 13-22. 1896. Diagnoses of new Tertiary fossils from the southern United States. Proce. U. 8. Nat. Mus., vol. 18, pp. 21-46. 1903. Op. cit. pt. VI, pp. 1219-1654, pls. XLVIII-LX. Defrance, M. 1819. Mémoire sur un nouveau genre de mollusque. Journal de Physique de Chemie, d’histoire naturelle et des Arts, avee des planches en taille- douce, t. LXXXVIII, pp. 215-219, 1 pl.
*References mentioned in the text and not ineluded here may be found eomplete in Palmer, 1937, bibliography.
22 g BULLETIN 112 326
Gregorio, Antoine de 1890. Monographie de la fauna Locénique de l’Alabama et surtout de celle de Claiborne de l’étage Parisien ... Ann. de Géol. et Paléont., 7 et 8 liv., 316 pp. 46 pls. Hanley, Sylvanus 1855. Ipsa Linnei Conchylia. 556 pp., V pls. Harris, Gilbert Dennison 1895. Claiborne fossils. Bull. Amer. Paleont., vol. I, No. 1, 52 pp., Lipps Heilprin, Angelo 1880. On some new lower Eocene Mollusca from Clarke Co., Alabama, with some poinis as to the stratigraphical position of the beds con- taining them. Acad. Nat. Sci., Philadelphia, Proc., vol. 32, pp. 364-375. 1891. The Eocene Mollusca of the state of Texas. Acad. Nat. Sci., Phil- adelphia, Proc. for 1890, vol. 42, pp. 393-406, pl. XI. Lamarck, Jean Baptiste Pierre Antoine de Monet de 1804. Swite des Mémoires sur les fossiles des environs de Paris. Genre XXVIII, XXVIII. Ann. Mus. Nat. Hist. nat. t. 4, pp. 46-55. Lea, Henry Carey 1848. Catalogue of the Tertiary testacea of the United States. Acad. Nat. Sci. Philadelphia, Proc., vol. 4, pp. 95-107. Lea, Isaac 1833. Contributions to Geology. Philadelphia, Pa. 227 pp., 6 pls. Martin, Karl 1891-1906. Die fossilien von Java. Bd. I. Gasteropoda. Leiden. 332 pp., 45 pls. Orbigny, Alcide d’ (See Sagra.) Palmer, Katherine VanWinkle 1987. The Claibornian Scaphopoda, Gastropoda and dibranchiate Cepha- lovoda of the southern United States. Bull. Amer. Paleont., vol. VII, No. 32, pt. 1, 548 pp.; pt. 2, 549-730 pp., 90 pls. Pilsbry, Henry Augustus and Bequaert, Joseph C. 1923. The type of Plotia ‘‘ Bolten.’’ The Nautilus, vol. 37, No. 1, p. 36. 1927. The aquatic mollusks of the Belgian Congo. With a geographical and ecological account of Cengo malacology. Bull. Amer. Mus. Nat. Hist., vol. LIII, pp. 69-602, pls. X-LXXVII. Remer, Ferdinand 1848. Contributions to the geology of Texas. Amer. Jour. Sci., 2d ser., vol. VI, pp. 21-28. Sacco, Federico 1892. £ molluschi dei terreni terziarit de Piemonte e della Liguria. Boll. Musei Zool. Anat. comp., Torino, vol. VII, N. 121, pp. 51-57. Sagra, Ramon de la 1845. Historia fisica politica y natural de la isla de Cuba. Pt. 2. His- toria natural. T. V. Moluscos. [by D’Orbigny] Paris, 376 pp. Atlas. Stenzel, Henryk Bronislaw 1940. The Yegua problem. Univ. Texas Pub. 3945, pp. 847-910, pls. 48-51. Stenzel, H. B. and Turner, Francis Earl [1942.] Type invertebrate fossils of North America. Eocene. Gastropoda. Bureau of Economie Geology, Austin, Texas. 92 eards. Veatch, Arthur Clifford 1902. The geography and geology of the Sabine River. Geol. Sur. Rept. Louisiana for 1902, Spee. Rept. No. 3, pp. 101-148, pls. XXIV-XXVII. 1902. Notes on the geology along the Ouachita. Op. cit., Spee. Rept. No. 4, pp. 149-172, pls. XXXVII, XXXIX. Wreiclev, Arthur 1938. Pngitsh Hocene and Oligocene Strombide and Aporrhaide. Proce. Mal. Soc. London., vol. XXIII, Pt. Il, pp. 61-68, pls. 4-6.
PLATES
PEATE 1m (25)
24 BULLETIN 112 328
EXPLANATION OF PLATE 1 (25)
Figure Page
1-23 Abderospira Aldrichi’ (Wangdon)) 222 EEE 20 Holotype. Height, 4.5 mm.; greatest diameter, 3 mm. Gos- port sand, Claiborne, Ala. The Johns Hopkins University. 3. /Coptostoma rameum).n. (Sp. ee ee 19 Height, 11.5 mm.; greatest diameter, 7 mm. Lower Clai- borne, Louisiana. No. 4455, Pal. Res. Inst.
4-5. Architectonica (Granosolarium) meekana Gabb — ~~. 12 Syntype. About x 38. Lower Claiborne, “Caldwell” area, ‘Texas. Acad. Nat. Sci. Philadelphia.
6-7. Architectonica (Granosolarium) meekana Gabb _....———sté—“<—«~CY' Syntype. About xX 8. Lower Claiborne. “Caldwell”. area, Texas. Acad. Nat. Sci. Philadelphia.
8. Architectonica (Granosolarium) texcarolina, n. sp. — ~~ 15 Paratype. Height, 2 mm.; greatest diameter, 4 mm. Lower
Claiborne, Little Brazos River, Texas. No. 4456, Pal. Res. Inst.
9-11. Architectonica (Granosolarium) texcarolina, n. sp. —~ 15 Holotype. Height, 2.3 mm.; greatest diameter, 5 mm. “Lower Claiborne, Little Brazos River, Texas. No. 4457, Pal. Res. Inst. 12. Turritella rina Palmer —— 17 Height, 30 mm.; greatest diameter, 9.3 mm. irowen Claiborne. Lapiniére Landing, Ouachita River, La. No. 4458, Pal. Res. Inst. 13. Turritella rina Palmer —~ (ou A Height, 30 mm.; greatest diameter, laa mm. same loc. as fig. 12. No. 4459, Pal. Res. Inst. 14. Turritella rina Palmer _ pupae e TL'y/ Height, 30.3 mm.; greatest diameter, 8.2 - mm. Same loc. as figs. 12, 18. No. 4460, Pal. Res. Inst. 15. Turritella rina Palmer —— benamreael tate )7/ Height, 32.4 mm.; greatest diameter, ole mm. ipsam loc. as figs. 12-14. No. 4461, Pal. Res. Inst. 16. Turritella rina Palmer —~ cha eerumepem nme e917) Height, 30 mm.; greatest diameter, sik mm. Same loc. as figs. 12-15. No. 4462, Pal. Res. Inst.
PL. 25, VOL. 28 BULL. AMER. PALEONT. No. 112, Pu. 1
26 BuLuetTin 112 330
EXPLANATION OF PLATE 2 (26)
Figure Page
123 HMipponix vaeus, mei iSpy ee es ee Holotype. Height, 10 mm.; greatest diameter, 22 mm. Gos- port sand, Claiborne, Ala. Ala. Mus. Nat. Hist.
4-6. Calliostoma (Eutrochus) eclaibornianum, n. sp. titi
Holotype. Height, 6.4 mm.; greatest diameter, 6 mm. Gosport sand, Claiborne, Ala. Ala. Mus. Nat. Hist. ees lena curren cal AVE tna rn S ple ee ee ee
Holotype. Height, 17.8 mm. : greatest ‘diameter, 8.1 mm. Gos- port sand, Claiborne, Ala. Ala. Mus. Nat. Hist.
9-10. Epitonium (Crisposcala) failianum, n. sp. — Wee see's 15) Holotype. Height, 12 mm.; greatest diameter! ca mm. - Jack- sonian or Claibornian, near Iail, Ala. Ala. Mus. Nat. Hist.
11-13. Epitonium (Gyroscaia) megiameriwz, n. sp. —— 6 Syntypes. Fig. 11, height, 15.4 mm.; ereatest diameter, “12.5 mm. Fig. 12, height, 22 mm.; greatest diameter, 14.5 mm. Fig. 18, height, 20.5 mm.; greatest diameter, 10 mm. Lower Claiborne near Gilbertown, Ala. Ala. Mus. Nat. Hist.
“1
PL. 26, VOL. 28 Buu. AMER. PALEONT. No. 112, PL. 2
“MAY 1 1904
Lier aat—
" PaLBonToLoarear Haske coe INSTITUTION _ Ivwaca, New YorK - U. Ss. A; if}
Notice !
This permanent record copy is printed on
all rag baper.
BULLETINS OF
AMERICAN PALEONTOLOGY
Vol. 28
No. 113
NEW FORAMINIFERAL GENERA FROM THE CUBAN MIDDLE KOCENE
By
W. Storrs Cole and Pedro J. Bermudez
May 4, 1944
PALEONTOLOGICAL RESEARCH JNSTITUTION Irpaca, New YorK SecA
x #& Coma.™~
te eology ir) ” : MAY 11 1944
LIBRARY
(AG /
NEW FORAMINIFERAL GENERA FROM THE CUBAN
MIDDLE EOCENE By W. Storrs COoLe Columbus, Ohio and
PEpro J. BERMUDEz Habana, Cuba
INTRODUCTION
Karly in 1943 Bermudez sent Cole selected specimens from 1o stations in the Eocene of Cuba. The stations represented are:
Ila
IO.
Station 158—Southwest of Cayo Ballenatos, north of Camaguey Province.
Station 481—North of Grua 9, Ramal Juan Criollo of Cen- tral Jatibonico, Camaguey Province.
Station 222—Cut in road from Managuaco to Nazareno, Habana Province.
Station 464—Punta Brava, Habana Province.
Station 110—850 meters northwest of Penon, Matanzas Province.
Station 322—1 kilometer south of Central Saratoga, Ma- tanzas Province.
Station 337A—+4.5 kilometers west of Guanajay on the road to Mariel, Pinar del Rio Province.
Station 246—3 kilometers southeast of Hotel Saratoga, San Diego de los Bafios, Pinar del Rio Province.
Station 261—Loma Candela, San Diego de los Banos, Pinar del Rio Province.
Station 527—East of Jicotea near Carretera Central, Santa
Clara Province.
4 BULLETIN 113 334
Cushman and Bermudez (1936a; 1936b; 1937) have described specimens of Foraminifera from three (Station 110, 261, 337A) of these localities. The only species discussed by Cushman and Bermudez (1936b, p. 59, pl. 10, figs. 27-30) in the present col- lection was Pseudorbitolina cubensis Cushman and Bermudez. Bermudez (1937, pp. 330-330) published a detailed list of the Foraminitera from Station 337A which he gave as one of the important faunal stations in naming the Jabaco formation which he correlated with the Tantoyuca formation of the Tampico Em- bayment area.
Coley G@os41, pp. 22,23 ply 2 . 5-1 i 1942, pp. 18),cO;plemas hig. 4; pl. 5, d1g..1 5 1O44, pp: oe a ke fig. 7; pl. 8, figs. ian ple rah iigss 12) identired Peon eenesouin cubensis in several wells in Florida. it is now apparent from this study that the Florida specimens are of the same species as those described from Cuba, but these specimens do not belong to the genus Pseudorbi- tolina. ‘They represent a new genus which is named Eodictyoco- NUS.
Bermudez (1937, p. 333) reports that Gunteria floridana Cush- man and Ponton occurs with Eodictyoconus cubensis (Cushman and Bermudez) at Station 337A. In the present collection Dictyoconus americanus (Cushman) was found in association with Eodictyoconus cubensis. Cole (1942, pp. 7, 8; 1944, pp. 25, 26) has demonstrated that these species are characteristic of the middle Eocene Lisbon limestone which is a distinct subsurface unit in Florida. It is evident that a portion of the Jabaco forma- tion of Cuba is middle Eocene in age rather than upper Eocene as the previous correlation with the Tantoyuca formation would sug- gest. The Tantoyuca formation has been correlated with the Jack- son formation. Muir (1936, p. 118) has suggested “future study may show the basal part of the Tantoyuca to be a facies of the upper Tempoal”. Cole (1927) believes that the upper Tempoal represents the Guayabal formation, a unit which is distinct from the underlying Tempoal.
or
335 CUBAN FORAMINIFERA: COLE AND BERMUDEZ
DESCRIPTION OF GENERA AND SPECIES
Family VALVULINIDA Genus CAMAGUEYIA Cole and Bermudez, new genus
Genotype—Camagueyia perpleca Cole and Bermudez, new species
Test in the early stages with several chambers to the whorls with some reduction of the number of chambers in the adult por- tion of the test; wall finely arenaceous with considerable cement ; chambers low, compressed, between thick roofs and floors; roo’s and floors not extending to the center of the test which has pillar- like structures, particularly near the aperture; aperture located in the center of the truncate apertural face surrounded by inward projecting teeth.
The shape of the test and arrangement of the chambers in Camagucyia suggest the imitial portion of Tritaxilina Cushman. Although numerous specimens were available, none of these showed the marked reduction in the number of chambers to a whorl which characterizes Tritaxilina. The aperture of Tritax- ilina becomes terminal in the adult stage with a series of inward
1 34
projecting teeth. In the initial stages the aperture is simple. aperture of Camagueyia is similar to that cf the adult stage Tritaxilina, but occurs in a form of test which wouid be consid- ered the initial stage in Tritaviline. The development of the pil- larlike structures below the aperture is not found in 7ritaxilina. Camagueyia may be the ancestor of Tritaxilina. Camagueyia perplexa Cole and Bermudez, n. sp. Plate 1, figs. 2, 3
Test conical, the initial end tapering, the apertural face trun- cate or very slightly concave, early chambers indistinct, becom- ing more pronounced in the adult whorls; sutures in the initial portion indistinct, flush with the surface of the test, followed by rather distinct, depressed sutures between raised chamber wails; wall finely arenaceous with large amounts of calcareous cement ; aperture large, in the center of the apertural end, surrounded by inward projecting teeth.
Axial sections show narrow, compressed chambers between very thick roofs and floors. The center of the test has a few pillars developed near the aperture below which the central area
6 BuLLeTIN 113 336
may be open as the chamber walls do not extend to the center of the test. Horizontal sections were not very satisfactory, but these showed a clear central area into which several teeth pro- jected.
An average specimen has a length of 0.8 mm, and a diameter at the apertural end of 0.8 mm. The largest specimen has a length of 1.0 mm. and a diameter at the apertural end of 0.7 mm.
Localities.Stations 158; 246; 201; 337A.
Genus DICTYOCONUS Blanckenhorn, 1900
Dictyoconus americanus (Cushman) Plate 3, figs. 6-10
Conulites americana Cushman, 1919, Carnegie Inst. Wash. Publ. 291, p. 43, text fig. 3.
Dictyoconus americanus Cole, 1942, Florida Geol. Survey Bull. 20, pp. 21- 24, pl. 3, figs. 12, 13; pl. 6, figs. 1-9; pl. 7, figs. 1-5; pl. 16, figs. 14, 15 (references and synonymy ).
Specimens from Station 261 possess the essential features of
this species. Genus EODICTYOCONUS Cole and Bermudez, new genus
Genotype.—Pseudorbitolina cubensis Cushman and Bermudez
Test regularly or irregularly conical, some specimens with a deeply excavated umbilicus, others with the umbilical area com- pletely filled with tiers of chamberlets. Specimens with the well- developed umbilicus are composed of a single layer of chambers, many of which contain a single horizontal plate. Specimens with the umbilical area filled with chamberlets have a plate, through which there are several large perforations, covering the umbilical area on the base of the test. The embryonic apparatus is composed of three subspherical chambers situated at the apex of the test.
Eodictyoconus cubensis (Cushman and Bermudez)
Plate 1, fig. 1; Plate 2, figs. 1-12; Plate 3, figs. 1-5
Pseudorbitolina cubensis Cushman and Bermudez, 1936, Contrib. Cush-
man Lab. Foram. Res., vol. 12, p. 59, pl. 10, figs. 27-30; Cole, 1941,
Florida Geol. Survey Bull. 19, pp. 22, 23, pl. 2, fig. 5-11; Cole, 1942,
ibid., Bull. 20, pp. 18, 19, pl. 3, fig. 4; pl. 5, fig. 1; Cole, 1944, ibid., Bull. 26, pp. 35, 36, pl. 2 fig. 7; pl. 8, figs. 14, 15; pl. 13, figs..3, 2:
Douvillé (1910, p. 57) described the genus Pseudorbitolina as
follows: Coquille convexo-concave, constituée par un test sableux, finement ré-
337 CUBAN FORAMINIFERA: COLE AND BERMUDEZ 7
ticulé sur face supérieure qui est ornée de fines lignes d’accroissement; la face inferieure présente sur son pourtour un limbe annulaire ayee une seule rangée d’ouvertures correspondant 4 un canal principal annulaire; des canaux analogues se succédent réguliérement jusqu’ au sommet. Entre ces canaux et la surface externe se développent tout un systéme de canaux rayonnants tubulaires, disposés en couches suecessives correspondant aux bandes d’accroissement.
This genus was illustrated by four external views, two dia- grams of the surface sculpture and one axial section. Unfortu- nately, all of these were drawings.
Cushman and Bermudez (1936, p. 59) referred Cuban speci- mensito this genus. Cole (1941, p. 22; 1042, p. 18; 1944, p. 35) recognized that specimens from Floridian wells were the same as those described from Cuba by Cushman and Bermudez. Ber- mudez (letter dated March 10, 1943) wrote Cole stating that he did not believe the Cuban specimens should have been referred to the genus Pseudorbitolina.
Cushman and Bermudez (1936, p. 59) presented an excellent description of the external features of the species they referred to Pseudorbitolina. Cole illustrated the internal features of the Flor- idian specimens assigned to the Cuban species. Inasmuch as the internal features of P. cubensis Cushman and Bermudez have not been described or illustrated, four axial sections and one hori- zontal section made from topotype specimens will be described and illustrated.
Horizontal section.—This section measures 1.46 mm. by 0.74 mm. The central open portion measures 0.74 mm. by 0.30 mm. The wall surrounding the umbilicus is divided into chambers having a length of roo to 120 w and a width of about 20 uw on the long sides of the test. The chambers on the short, curved ends of the test have a length of as much as 220 uw and a width of as much as 100 uw. Many of these chambers are subdivided by a vertical plate which extends from the peripheral side of the chamber one- half to three-quarters across the chamber opening. The radial chamber walls on the straight sides of the test end in an irregu- lar wall which partially surrounds the umbilicus, but on the curved short ends the radial chamber walls bifurcate into two short processes which do not seem to be connected with each other nor with any wall of the umbilicus. Along one of the
8 a ia BuuLetin 113 338
straight sides on the peripheral edge there is a row of small cham- berlets. The horizontal floors and roofs of the chambers are per- forate. The perforations are of two types: small dark dots and large round openings of which about three occur to a chamber. Many of the radial chamber walls have a fine dark line through the center.
Axial sections —The first section to be described has a diame- ter at the base of 1.1 mm. and a height of 0.66 mm. The umbili- cus has a basal diameter of 0.5 mm. and a height of 0.4 mm. The test 1s composed of a single layer of chambers arranged so that the long axis of the chambers is parallel to the base of the test. These chambers have a length of about 260 uw and height of about 60 uw. A single horizontal plate projects abcut 80 mw into each chamber from the external wall. The most notable feature of this section is the fact that two of the three embryonic cham- bers are shown. The larger chamber has an internal length of 200 p and an internal height of 140 yw; the smaller chamber has an in- ternal length of 80 uw and an internal height cf 90 uw. The wall surrounding these chambers has a thickness cf about 20 mu.
The second section represents a specimen with a basal diameter of 1.22 mm. and a height of 0.84 mm. The umbilicus has a basal diameter of 0.6 and a height of about 0.5 mm. The test is com- posed of a single layer of chambers arranged so that the long axis of the chambers is parallel to the base. Average chambers have an internal length of about 180 uw and an internal height of about 50 u. The floors of the chambers bend downward as they leave the periphery of the test, then curve sharply so that they be- come parallel with the hase of the test and finally as they approach the umbilicus they bend gently toward the apex of the test and touch the floor of the next chamber above. Some of the umbili- cal ends of the floors do not quite touch the floor of the next chamber in which case a narrow passage is left. These chambers are simple, without the projecting horizontal plate observed in the first section described.
The third section was made from a low, spreading individual with a basal diameter of 2-+ mm. and a height of about 0.6 mm. The umbilicus has a basal diameter of about 0.6 mm. and a heicht
339 CuBAN FORAMININERA: COLE AND BERMUDEZ 9
of about 0.4 mm. The structure of the chambers composing the test is irregular (see Plate 2, figure 7).
The fourth section was made from a much larger individual with a basal diameter of 3.2 mm. and a height of 2.9 mm. This specimen, viewed from the apex, had a triangular cross section. The umbilicus was covered by a plate in which there were several distinct openings. The test is composed of a peripheral layer of chambers similar to the ones observed in the other sections ex- cept that they are larger, but this specimen instead of having an open umbilicus has that area partially filled by small chamberlets.
Although the preliminary decision was made that this large specimen might represent a different genus, study of a large suite of specimens from Station 261 demonstrated that such was not the case. An analysis of the specimens from Station 261 follows.
The specimen illustrated on Plate 1, figure 1 has a basal diam- eter of 1.2 mm. and a height of 0.54 mm. The basal diameter of the umbilicus is 0.6 mm. and the height of the umbilicus is 0.36 mm. The test is composed of a single layer of chambers, some of which possess a single horizontal plate. At the apex a portion of a single embryonic chamber is shown.
A slightly larger specimen with a basal diameter of 1.46 mm. and a height of 0.8 mm. is illustrated on Plate 2, figure 3. The umbilicus of this specimen has a basal diameter of 0.6 mm. and a height of 0.5 mm. The structure of the test is similar to that observed in the first thin section described from this station.
The specimen illustrated on Plate 3, figure 5 demonstrates the connection between the specimens which are composed of a single layer of chambers and possess a deep umbilicus and those which have the umbilical area partially filled with chamberlets. This specimen which has a basal diameter of about 2 mm. and a height of 1.6 mm, has its test composed of a peripheral layer of chambers similar to those specimens which are composed of this layer alone. However, there is a mass of chamberlets developed at the base and extending into the umbilical area. The embryonic chambers observed in this specimen are similar to those previously described
10 j BULLETIN 113 340
from a topotype of “Pseudorbitolina”’ cubensis.
The specimens illustrated on Plate 2, figures 2, 4, 6 are a con- tinuation of the series which proves that this genus contains spec- imens in which the test is composed of a peripheral layer of chambers enclosing a deep, well-developed umbilicus to those specimens which have the umbilical area completely filled with layers of chamberlets.
Pseudorbitolina marthe Douvillé, the genotype of Pseudorbit- olina, is similar to many of the Cuban specimens in that the test is concavo-convex, and is composed of a single layer of chambers. However, this similarity is superficial because the details of the internal structure are different.
As Douvillé indicates Pseudorbitolina is somewhat similar to Orbitolina, whereas Eodictyoconus is closely related to Dicty- oconus, particularly through the specimens which have the um- bilical chamberlets developed.
Localities —Stations 110; 261 ; 337A.
Family AMPHISTEGINIDAS
Genus EOCONULOIDES Cole and Bermudez, new genus Hoconuloides wellsit Cole and Bermudez, new species
Genotype.
Test conical with an involute, trochoid, multichambered spire, the final chambers subdivided on the peripheral side into small chamberlets. The embryonic apparatus is bilocular, consisting of a subspherical initial chamber and a smaller second chamber. The spiral wall is thick initially and possesses irregularly devel- oped pillars. The final spiral wall is thinner and lacks pillars.
Eoconuloides is related to Helicostegina Barker and Grimsdale (1936, p. 233). The embryonic apparati in the two genera are the same. But, the most primitive species of Helicostegina has well- developed subsidiary chamberlets. These are not found in Eoconuloides although there is a suggestion of the development of this type of chamberlet. The axial sections of Helicostegina show biconvex forms, but Eoconuloides has a remarkable conical shape which produces triangular axial sections. Eoconuloides is
341 CUBAN FORAMINIFERA: COLE AND BERMUDEZ stil
a specialization of the Helicostegina type by the axial elongation of the test.
Eeconuloides wellsi Cole and Bermudez, n. sp. Plate 1, figs. 4-10
Test conical, the base flat or very slightly convex, apex bluntly rounded, peripheral angle subacute, surface smooth, but in well- preserved specimens there is a mesh of clear shell material which outlines opaque areas. ‘The mesh is composed of semicircular bands with the convex portion oriented toward the base of the test. The apical side of an individual unit of the mesh is formed by two intersecting convex sides of the succeeding row of units. The external dimensions of five specimens follow:
Specimen I 2 3 4 5 (type) iHMeight 9/10 mm: | T.0mm:||) 0.8 mm. ) 1.36)mm., | 1.4mm. Diameter of
base o.96mm. 1.16mm. o0.88mm. 1.26mm. 1.14 mm.
The embryonic apparatus is bilocular, the initial chamber is subspherical with internal diameters of 40x60 yp, the second cham- ber is smaller with internal diameters of 30x40 uw. The distance across both chambers including the chamber walls is too uw. The division between the chambers is thin and straight. The outer chamber wall is relatively thick.
A horizontal section with a diameter of t.02 mm. has 34 coils with 25 chambers in the final volution. The chamber walls are straight, and many of them have a slight expansion on their prox- imal ends. There appears to be an aperture between this ex- panded portion of the radial chamber wall and the spiral wall, however, the preparations were not sufficient to be absolutely cer- tain. One slightly oblique horizontal section indicates that the final chambers are subdivided into chamberlets in the peripheral portion.
Axial sections show the trochoid character of the test. The spiral wall has differences in thickness. The inner part has a thickness of 100 uw but the peripheral wall may be as thin as 30 p. The thicker walls possess irregularly developed pillars. The heads of the pillars project above the surface of the walls. There is considerable difference in the strength of the pillars between in-
12 BULLETIN 113 342
dividuals. The thin peripheral walls appear to lack pillars which vould account for the absence of surface ornamentation. This species is named in honor of Dr. John W. Wells. Locality.—Station 222.
Family PLANORBULINIDZ Genus EOANNULARIA Cole and Bermudez new genus
Genotype.—Eoannularia eocenica Cole and Bermudez, new species
Test small, fragile, flat or concavo-convex, with or without a small umbo on the convex side. Embryonic apparatus bilocular ; either a small, circular initial chamber slightly embraced by a larger chamber, or an ovoid initial chamber completely embraced by the second chamber. [Equatorial chambers of two types, those of the annuli adjacent to the embryonic apparatus have curved outer walls and truncated inner ends, those in the final annuli are regularly rectangular with the radial walls in adjacent annuli alternating in position, The entire thickness of the test is com- posed of the equatorial layer, except a slight deposit of clear shell material over the embryonic apparatus.
Eoannularia has coarsely perforate, calcareous walls similar to Linderina. The embryonic apparatus, the shape and arrangement of the initial embryonic chambers are similar to those of Linder- ina. However, the equatorial chambers of the final annuli are similar to those of Cycloclypeus. Linderina has a very thick layer of clear shell material over the central portion of the test. Eoannularia eocenica Cole and Bermudez, n. sp. Plate 1, figs. 11-16
Test small, fragile, circular, flat or concavo-convex, usually with a small, distinct umbo on the convex side, diameter from 0.6 to 1.32 mm. Many specimens have a thickened central area surrounded by a thinner portion from which the test slowly thick- ens toward the periphery. A typical specimen with this type of cross section has a thickness of 0.14 mm. at the center of the test, a thickness of 0.8 mm. at a distance of 0.14 mm. from the center, and a thickness of 0.12 mm. at the periphery. The surface of the test is ornamented by a regular mesh formed by the walls of the equatorial chambers, observed especially if the surface of the test is wet. Specimens with umbos have the mesh only on the pe-
343 CUBAN FORAMINIFERA: COLE AND BERMUDEZ 13
ripheral portion of the test as the umbo is composed of clear shell material which effectively covers and conceals the equatorial layer.
The embryonic apparatus consists of two chambers. Two preparations have a small, circular initial chamber slightly em- braced by a larger chamber; a single thin section has an ovoid initial chamber completely embraced by a larger chamber. The following table presents the measurements of these three em- bryonic apparati:
Specimen I 2 2 Distance across both
chambers including
chamber walls 70 60 pu 120 pu Internal diameter or
diameters of initial
chamber 20 UL 20 pw 45X50 pb Internal diameter of
second chamber 22X40 ff 20X50 f “4Oxrro W Thickness of outer wall Tats 6 pu 15 p
At first the specimen with the larger embryonic apparatus was thought to represent another genus, but as the other characters are identical with the other specimens, it is included with them.
The embryonic apparatus is surrounded by about six annuli of equatorial chambers with curved outer walls and truncated inner ends. These equatorial chambers increase in size gradually. As this increase occurs the tangential diameter gradually becomes ereater than the radial diameter and the curvature of the outer wall becomes less, There is a gradual change from the inner annuli to the outer which are composed of regular, rectangular chambers which have a radial diameter of about 40 uw and a tangential diameter of about 60 wu. |The radial chamber walls of these rectangular chambers in adjacent annuli alternate in posi- tion.
The vertical sections show that the entire thickness of the test is composed of the equatorial chambers with the exception of a slight accumulation of shell material over the embryonic appara- tus. The walls of the equatorial chambers as viewed in vertical
14 BuLLETIN 113 344
sections are strongly concave toward the periphery. Numerous stoloniferous apertures occur in the chamber walls. Localities —Station 322; 337A; 464; 481; 527.
PITBRATURE! ChkED
Barker, R. Wright and Grimsdale, Thomas F. 1936. A contribution to the phylogeny ef the orbitcidal Foraminifera with a description of new forms from the Hocene of Mexico. Jour. Paieont., vol. 10, pp. 251-247, pls. 30-38 Bermudez, Pedro J.
1937. Foraminiferos pequenos de las margas Eocenicas de Guanajay, Provincia Pinar del Rio. Cuba, Mem. Soc. Cubana Hist. Nat., vol. 11, pp. 319-346, 1 map.
Cole, W. Sterrs
1927. A foraminiferal fauna from the Guayabal formation in Mexico. Bull. Amer. Paleont., vol. 14, No. 51, pp. 1-46, pls. 1-5.
1941. Stratigraphic and paleontologic studies of wells in Florida. Florida Geol. Survey Bull. 19, pp. 1-91, 18 pls., 3 figs.
1942. Stratigraphic and patleontologic studies of wells in Florida. No. 2, tbid., Bull. 20, pp. 1-89, 16 pls., 3 figs. No.
1944. Stratigraphic and paleontologic studies of wells in Florida. 3, t0td., Bull. 26, pp. 1-168, 29 pls., 5 figs. Cushman, Joseph A., and Bermudez, Pedro, J. 1936a. New genera and species of Foraminifera from the Hocene of Cuba. Contrib. Cushman Lab. Foram Res., vol. 12 pp. 27-38, pls. 5, 6. 1936b. Additional new species of Foramuuifera and a new genus from the Focene of Cuba. Tbdid., pp. 55-62, pls. 10, 11. 1937. Additional new species of Eecene foranuinifera from Cuba. Ibid., vol. 13, pp. 106, 107, pl. 16. Douville, Henri 1910. La Craie et le Tertiaire des environs de Royan. Soc. Géol., France, Bull., vol. 10, 4th sér., pp. 54-57, figs. 1-4. Muir, John M. 1936. Geology of the Tampico region, Mexico. Amer.
Geol., p. 118.
Assoc. Petrol.
PLATES
PAGE 1 (27)
16
11-16.
BULLETIN 113
EXPLANATION OF PLATE 1 (27)
346
Page
Eodictyoconus cubensis (Cushman and Bermudez), new genus
Axial section of a specimen which has only the peripheral layer of chambers, < 41, station 261.
Camagueyia perplexa Cole and Bermudez, new genus and new epecice Hii oy Sheed ny LS Ua xh A eh EEN Aen re Fig. 2, axial section of a paratype (Cole collection, No. 400),
x 41, station 158; 3, external views of 4 cotypes (Cole collection, No. 401), x 10, station 158.
Eoconuloides wellsi Cole and Bermudez, new genus and new SD GCI e's SICA VUNE IRAE ai Wie LIM i eae Se ATL ee ae pe 4 Fig. 4, external view of holotype (C ‘ole collection, No. 402),
x 10, station 222; 5-7, horizontal sections of 3 specimens, x 41, station 222; 8-10, axial sections of 3 specimens, x 41, station 222.
Eoannularia eocenica Cole and Bermudez, new genus and new
SPECIES wee uusuaus ae ih Bugs.” 10.2; vertical ‘sections of 2 "specimens; net “section
just past the center of the test, x 41, station 337A; 12
seetion of a megalospheric individual, paratype (Cole collection, No. 403), x 41, station 481; 13, 14, hori- zontal sections of 2 megalospherice individuals; 13, x 41, station 337A; 14, paratype (Cole collection, No. 404), x 41; station 481; 15, the central portion of figure 14, x 163; 16, external views of 3 specimens, x 10, upper specimen the holotype (Cole collection, No. 405), ’ station 481,
6
iat
12
Pt. 27, Vou. 28 Buu. AMER. PALEONT. No. 113, Pu. 1
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18 BULLETIN 113 348
EXPLANATION OF PLATE 2 (28)
Figure Page 1-12. Hodictyoconus cubensis (Cushman and Bermudez), new genus’ 6 Figs. 1-7, axial sections to illustrate stages of development; 8-12, horizontal sections; 1, 5, 7, 8, X 41, topotypes, sta- tion, 837A 2, td, 8, >< Mali, XK Lb, 1651 al onOoialS x 15, 12, x 41, station 261; 12 is an enlarged portion | of figure 10.
PL. 28, VOL. 28 Buu. AMER. PALEONT. No. 113, Pu. 2
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20 BuLLetin 113 350
EXPLANATION oF PLATE 3 (29)
Figure Page
1-5. Eodictyoconus cubensis (Cushman and Bermudez), new genus’ 6 Fig. 1, section parallel to the surface of the test to illustrate the arrangement of the chamberlets, x 41, station 261; 2, horizontal section of irregularly shaped specimen, < 15, station 261; 3, horizontal section from 680 feet in the Rh. V. Hill well (W-8) neay ‘lampashores (formerly Olds- mar, Hillsborough County, Florida) intreduced for com- parison with the, Cuban specimens, » 15; 4, horizontal section, < 41, to illustrate details of the chambers, sta- tion 261; 5, axial section, X 41, station 261. 6-10. Dictyoconus ‘americanus (Cushman) 2. 52922 2 Fig. 6, axial section, X 15, station 261; 7, portion of figure 6, < 41, to illustrate the plates in the peripheral cham- bers; 8, horizontal section, x 15, station 261; 9, axial section, < 15, station 261; 10, portion of figure 8, x 41.
PL. 29, VoL. 28 BuLu. AMER. PALEONT. No, 113, Pu. 3
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RESEARCH INSTITUTION
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BULLETINS
OF
AMERICAN PALEONTOLOGY
Vol. 28
No. 114
THE LARGER FORAMINIFERA FROM SAN JUAN DE LOS MORKROS, STATE OF GUARICOC, VENEZUELA
By
© Mi. Bramine Gaudi
July 16, 1944
Paleontological Research institution
Ithaca, New York Uses Ae
‘JUL 25 1944
LipRAaky
CONTENTS
Page FN S{S| Rete VC) E), crest nea ee eee Perec eee rere eee ere re rea eR eee i) JNCGHSIACA yy AKEXG Ws OY SY 01 Fe eee kere aed eater Pe EERE ferme tt ere er 5 IDescruptommot i thei aerial snl sse meee eee ec Rrra ge i ener eee estan eh Uoeeeeee 6 Palsontolo c1cale anno Gey Omsyy eee cece cece te cecre ee eet tee meee eee eee ae een 10 PSY S GMM cated CCL ES CATO LO LYS i eet eee ese er eee econ ar eee ee Sete eer ae Hal AEN GCS Was WAVE SEA ALE ERD ie ce eer recede ete areca eecepoerma beter 24 The correct stratigraphical place of the Soldado een Rear rca ete 32
The vertical distribution of the Upper Cretaceous and lower Tertiary larger Foraminifera in the region around the Caribbean and the Gulf OlpMexa Con Gwiltihech ant) paces eee enna
Annotations to the tentative distribution chart
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THE LARGER FORAMINIFERA FROM SAN JUAN DE LOS MORROS By C, M. Bramine Caudri
ABSTRACT
The fauna in limestone samples from San Juan de los Morros, State of Guarico, Venezuela, was found to be of Paleocene age. Seven species of larger Foraminifera are described, two of which as new (Hexagonocy- clina meandrica and Discocyclina aguerreverei), two new gencric names (Hexagonocyclina and Ranikothalia) are proposed and the nomenelature of the American ‘‘ Miscellaneas’’ is discussed. A general discussion on the relative age of the Soldado formation and the vertical distribution of the Upper Cretaceous and lower Tertiary larger Foraminifera in this re- gion concludes the paper.
ACKNOWLEDGMENT
Early in 1941 Dr. S. E. Aguerrevere, geologist of the Minis- terio de Fomento, Venezuela, presented a small collection of rock samples containing larger Foraminifera from San Juan de los Morros, State of Guarico, to Dr. H. G. Kugler at Pointe-a- Pierre, who assigned the examination to me.
After the preliminary results had turned out to be of general interest, it was decided that they should be worked out for pub- lication. It is a privilege to acknowledge here the help from all those who made this work possible by their interest and assist- ance. S. E. Aguerrevere furnished the information on the stra- tigraphical position of the samples, H. Baggelaar, T. F. Grims- dale, U. Haanstra, H. G. Kugler and A. Senn lent me literature from their private libraries, whereas T. W. Vaughan sent us copies of a private correspondence between himself, L. M. Davies and S. Hanzawa on the subject of the nomenclature of the Miscellaneas. My special thanks go to H. H. Renz for his ad- vice and help in supplying literature, to T. F. Grimsdale for many elucidative discussions and for supplying me with type specimens for comparison, and especially to A. Senn, of Bar- bados, who very kindly took the trouble of showing me the vari- ous localities in the Scotland District of that island, in order that I might gain some insight in the character of the highly inter- esting upper Scotland formation.
6 BULLETIN 114 356
Mrs. Dorothy K. Palmer prepared for use in the Pointe-a Pierre Geological Laboratory a carefully chosen collection of types from Cuba, for which I wish to express my gratitude. Cir- cumstances did not, however, permit me more than a superficial examination of this material, so that all the remarks made on Cuba in the following pages have to be considered as based only on published literature and on a couple of Cretaceous types pre- viously received from T. F. Grimsdale.
I am greatly indebted to Trinidad Leaseholds Limited for their permission to insert data obtained from their material for the pur- pose of comparison with the San Juan fauna,
Finally, I want to thank the Imperial College of Tropical Ag- riculture in Trinidad for generously offering me facilities for the completion of my manuscript and the preparation of the photo- graphs.
DESCRIPTION OF THE MATERIAL
The material at my disposal consisted of 11 samples of hard foraminiferous limestone, collected at San Juan de los Morros, State of Guarico, Venezuela. These samples and many sections prepared from them are kept in the collections of the geological laboratory of Trinidad Leaseholds Ltd., Pointe-a-Pierre, Trini- dad B. W. I., while duplicates of the samples are kept by the Servicio Tecnico de Mineria y Geologia in Caracas. The holo- types or syntypes of the new species and hypotypes including all the photographed specimens were sent to the U. S. National Museum, Washington, D. C.
The samples can be described as follows:
G.41. Locality—Foot of Morro with lighthouse Discocyclina aguerreverel, n. sp. (common) Athecocyclina cf. cooket (Vaughan) (scarce) Lepidorbitoides cf. planasi M. G. Rutten (common) Ranikothalia antillea (Hanz.), R. tobleri (V. and C.) and RR. soldadensis (?) (V. and C.) (abundant)
357 VENEZUELAN FORAMINIFERA: CAUDRI 7
G.86. Locality—Saddle to the south of the Morro with light- house (see fig. 1) Discocyclina aguerreverei, n. sp. (scarce) Ranikothalia antillea (Hanz.) (scarce)
G.gta. Locality—South slope of Morro de la Puerta Ranikothalia antillea (Hanz.) (abundant) Ranikothalia toblerit (V. and C.) (abundant) Tubiform porous organisms, ind, (abundant) (fig. 2
G.gtb. Locality—as G.gta Athecocyclina cf. cookei (Vaughan) (abundant) (figs. 5, 6, 18, 20)
Lepidorbitoides cf. planast M. G. Rutten (abundant) (fig. 10)
Rantkothaha antillea (Hanz.) (common) (figs. 5, 15) Ranikothalia tobleri (V. and C.) (abundant) Rantkothalia ? soldadensis (V. and C.) (scarce) (fg. 26)
G.125c. Locality—Small Morro NW. corner valley Discocyclina aguerreverei, n. sp. (abundant) (figs. 8, Els oe 7)
Athecocyclina cf. cooket (Vaughan) (common) (fig. 12)
Lepidorbitoides cf. planasi M. G. Rutten (abundant) (fig. 14)
Lepidorbitoides, sp. ind. (scarce) (fig. 16) Rantkothalia antillea (Hanz.) (abundant) (fig. 23)
G.128. Locality—1 km. N. 50 E. from the hotel Discocyclina aguerreverei, n. sp. (abundant) Athecocyclina cf. cooket (Vaughan) (scarce) Hexagonocyclina meandrica, n. sp. (probably rather common) (figs. 7, 9)
Lepidorbitoides cf. planasi M. G. Rutten (common) Rantkothalia antillea (Hanz.) (scarce) Ramkothalia tobleri (V. and C.) (common)
G.153. Locality—ai1 km. SE. of Granja
Discocyclina aguerreverei, n, sp, (common)
BULLETIN 114 358
Athecocyclina cf. cookei (Vaughan) (scarce) Hexagonocyclina meandrica, n. sp. (scarce) Lepidorbitoides cf. planasi M. G. Rutten (common) Ranikothalia antillea (Hanz.) (common) (fig. 25) Ranikothalia ? tobleri (V. and C.) (scarce) Ranikothalia soldadensis (V. and C.) (scarce) (fig.
19)
G.164/165.Locality—Eastward along strike from G. 91
G.174.
G.219.
G.s.s.
? Discocyclina aguerreverei, n. sp. (one bad fragment) Athecocyclina cf. cooket (Vaughan) (common) Lepidorbitoides ci. planasi M. G. Rutten (scarce) (fig. 3) Rantkothalia antillea (Hanz.) (abundant) Ranikothalia tobleri (V. and C.) (scarce) (fig. 3) Locality —Along the Rio Guarico, 1500 m. downstream from the mouth of Quebrada Pagiita No larger Foraminifera Locality Quebrada de Agua, 2 km. SE. of San Juan No larger Foraminifera
Locality—15 km. from San Juan on the road to San
Sebastian
Discocychina aguerreverei, n. sp. (scarce) Lepidorbitoides cf. planasi M. G. Rutten (scarce, but unevenly distributed; in patches sometimes rather common)
Rantkothalia antillea (Hanz.) (common) (figs. 4, 21) Rantkothalia tobleri (V. and C.) (abundant) (fig. 22) Ranikothalia soldadensis (V. and C.) (common) (fig.
24)
Among these samples ten represent one lithological unit. It is a partly pseudo-oolithic highly fossiliferous limestone with, generally spoken, a uniform fauna containing both Nummulitidz and orbitoids. Only one piece from the locality G.g1, distin- guished for convenience as G.gia from the rest of the sample (G.gib), is slightly different.
359 VENEZUELAN FORAMINIFERA: CAUDRI 9
1. The pseudo-odlithic limestone.—This is a grey to brownish- grey recrystallized limestone, in places micro-breccious (G.128, 153) and often of a definitely odlithic appearance, which is, how- ever, caused by a peculiar kind of organisms that will be discussed below under the preliminary name of “tubiform ooliths” (Plate 1, figs. I, 3, 5). In general, this limestone carries the following faunal and floral assemblage:
Discocyclina aguerreverei, n. sp.
Athecocyclina cf. cookei (Vaughan)
Hexagonocyclina meandrica, n. sp.
Lepidorbitoides cf. planasi M. G. Rutten, ? sp. ind.
Ranikothalia antillea (Hanz.)
Ranikothalia tobleri (V. and C.)
Ranikothalia soldadensis (V. and C.)
Amphistegina
Rotaliidee
Globigerinidz
Textulariidz
Miliolidze
Gastropods
Lamellibranchs
Bryozoa
Echinoids
Corals
“Tubiform ooliths”
Corallina
Lithothamnium
Archeolithothamnium
Ranikothalia soldadensis and Hexagonocyclina meandrica are only exceptionally found, but both species are to be considered as regular components of the assemblage, their scarcity being re- sponsible for the fact that they are only occasionally showing up in the rock sections.
Of the accompanying organisms alge (mostly Corallina) and the so-called “tubiform ooliths” are as a rule abundant, whereas
10 BULLETIN 114 360
also echinoids and Bryozoa and in one case corals (G.125c) may play an important role as rock builders. Among the smaller Foraminifera only Miliolide (G.s.s.) and Rotaliide (G164/165) may be present in large amounts.
The samples G.174 and 219 have apparently no larger Fora- minifera, but their fauna, although slightly different from the others in having a much larger quantity of shell material (lamelli- branchs, small fragments), is closely linked with the rest by their abundance of “tubiform odliths”, particularly with the in- termediate sample G.86, which has hardly any larger Foramini- fera, that there is no doubt that they belong to the same rock as the samples that carry the complete fauna.
2. The non-odlithic foraminiferal limestone G.gta.—This is a typical Ranikothalia-limestone, containing both R. antillea and R. tobleri in large quantities and in the meantime lacking all kinds of “orbitoids’”. It is, furthermore, characterized by the abund- ance of a peculiar tubular organism of a much larger size than the above-mentioned “tubiform ooliths’”’ and with coarsely por- ous walls (Plate 1, fig. 2). Echinoids and lamellibranchs are common in this rock and also some gastropods and corals were observed.
In a reef area like the one under consideration sudden changes of fauna and the occurrence of severely restricted colonies of certain organisms can be expected. For that reason, not too much stress should be laid on the difference in fauna between G.gia and the other samples. Most probably both kinds of rock belong to the same deposit.
PALAKONTOLOGICAL ANNOTATIONS
Hard rocks like the ones discussed here are, as a rule, an un- favorable starting-point for the detailed description of a fauna. It is true that the student can eventually get all the necessary in- formation on the internal as well as on the external features of his species by means of orientated thin sections in addition to what he observed already in accidental rock sections and on the weathered surface cf his samples, but this method requires so
361 VENEZUELAN FORAMINIFERA: CAUDRI 11
much time that it can only be carried out for a very limited num- ber of specimens. The following extensive and general remarks may, therefore, seem somewhat unbalanced if compared with the small collection of rock material on which they are based. As a matter of fact, the author would not have dared to write them down if she had not already been familiar with practically all the species in question through the study of loose specimens from Trinidad, Soldado Rock and Barbados. As this study was, for the greater part, carried out in the laboratory of Trinidad Lease- holds Limited for confidential reports, that material can not be in- cluded in our descriptions, but it has to be mentioned here to support the author’s view on the systematic place of some of the forms and, at the same time, to furnish the indispensable data for the age determination of the San Juan fauna.
SYSTEMATIC DESCRIPHIONS
Genus DISCOCYCLINA Giimbel, s. str. Discocyclina aguerreverei, n. sp. Plate 2, figs. 8, 11; Plate 3, fig. 13; Plate 4, fig. 17 This form is closely related to D. grimsdalei Vaughan and Cole. It is practically indistinguishable from that species exter- nally and in vertical section, and also in horizontal section as far as the equatorial chambers are concerned. It should, however, be remembered that both species have up to now been found only in a recrystallized condition which may conceal original differ- ences in the structure, especially in the vertical section. The only conspicuous difference between the two species lies in the nu- cleoconch of the megalospheric form. D. grimsdalei has, in hori- zontal section, a “loose” initial chamber which does not touch the wall of the surrounding second chamber (it does, however, in the vertical section), whereas in D. aguerreverei the second chamber is kidney-shaped and embraces the first one only half or for three-quarters. As in D. grimsdalei, the test of D. aguerreverei varies from discoid, sometimes with depressed center, to very flat with a thin edge. All the San Juan specimens are of the latter type; they
12 BULLETIN 114 362
are well preserved in the hard rock and show a diameter of up to 5 mm, (Discoid specimens are known from other localities. )
D. aguerreverei shows a certain resemblance to Vaughan’s D. blanpiedi from the lower Eocene of Alabama (1936, p. 254, pl. 41, figs. 1-7; see also Gravell and Hanna, 1938, pl. 7, figs. 1, 2, 3); but the latter seems to lack the thickened concentric walls which are so characteristic of the median layer of both D. grims- dalei and D. aguerreverei, it has smaller pillars and the lateral chambers have probably lower lumina and thicker walls in the vertical section.
Syntypes.—San Juan, G. 125¢.
Localities in San Juan.—G. 41, 86, 125c, 128, 153, 164/165 (G5 Ga Goss
Distribution in other areas.—Paleocene of Soldado Rock and Lizard Springs (Trinidad) ; Paleocene blocks from Point Bon- tour (Trinidad) (also forma B).
Genus HEXAGONOCYCLINA, n. gen. Genotype.—Discocyclina cristensis Vaughan (1924, 1929) Characteristics of the genus.—Test lenticular or discoid, of variable thickness, built up of a well-defined equatorial layer and lateral tissues. Embryonic apparatus small, consisting of two chambers which produce, in early development, two relatively large “auxiliary chambers” that in their turn give rise to four very short “nepionic spirals’' with two symmetric nepionic chambers over the middle of the embryonic ones. Early median chambers ogival, soon turning into the definite hexagonal shape with obtuse tops, very thin-walled (sometimes the concentric walls are locally thickened near the periphery so that the tops of the chambers are flattened and the chambers appear rectangu- lar, but there is no doubt that the hexagonal shape is the normal one). Concentric stolons at the distal end of the radial walls (see description of H. meandrica). Radial walls alternat- ing in subsequent rings of median chambers.
The place of the concentric stolons distinguishes Hexagono- cyclina froxa Discocyclina, s. str., in which they are at the prox-
1 In the sense of Tan Hok for Lepidocyclina and Miogypsina.
363 VENEZUELAN FORAMINIFERA: CAUDRI 13
imal end. This peculiarity would point to relationship with Pseudophragmina (esp. Proporocyclina), but the alternating ar- rangement of the radial walls prevents us from including our form in that genus. The small size of the nucleoconch and the aspect of the first median chambers reminds one at first sight of of Lepidorbitoides, but the nepionic pattern is fundamentally dif- ferent and the hexagonal shape of the later median chamber is also a marked difference. This nepionic arrangement and the shape of the median chambers are easily recognizable character- istics in Hexagonocyclina’.
Up to now, two or three species of Hexagonocyclina are al- ready known: two flat forms (Discocyclina cristensis Vaughan from the Chicontepee formation in Mexico, which has been chosen as the genotype, and our San Juan species, H. meandrica, which may prove to be identical with it) and a small, robustly lenticu- lar, as yet undescribed species that occurs in Trinidad and in Soldado Rock. The genus is, for the time being, considered as typical for the Paleocene.
Hexagonocyclina meandrica, n. sp. Plate 2, figs. 7, 9
Test very flat and thin, up to 3.6 mm. in diameter. Surface smooth or with small granulations; lateral chambers large, thin- walled, meandric (observed in tangential sections of the San Juan specimens in the rock, but even better on the surface of loose specimens from Soldado Rock).
Embryonic apparatus 100-120 » (measured across both cham- bers), consisting of two practically equal subglobular chambers. Two large auxilary chambers, nearly as big as the embryonic ones ; four nepionic spirals, each consisting of 1-3 chambers. Me-
dian chambers at first small and ogival soon becoming isodiame-
2 Both the nepionie pattern and the hexagonal chambers distinguish Hexagonocyclina from all other small-chambered orbitoids. A similar nepionie development is, up to now, only known from Lepidocycline, s. 1. and Miogypsine. Occasionally, hexagonal median chambers are also found in thin walled Discocycline, s. str. (e. g., Discocyclina blanpiedi Vaughan 1936, D. bullbrooki V. and C., 1941, ete.) or Asterocycline (e. g., the genus Orthocyclina Van der Vlerk, 1923; Caudri, 1934) but there is never such a distinct and constant feature as in Hexagonocyclina.
14 BULLETIN 114 364
tric hexagonal ; typical of the species seems to be that towards the periphery they become very much elongated radially and can at- tain a length of 85 ». Stolons were not actually observed any- where, but in several specimens from other localities, e. g., Sol- dado Rock, a thinning-out and even complete obliteration of the radial walls towards the distal end occurred and a distal position of the concentric stolons can be deducted from that peculiar fact. The vertical section can not be described from the San Juan material. The species is very closely related to Discocyclina cristensis Vaughan (see description 1929, Mexico, pp. 8-9, pl. 2, figs. 1, 2) or it may be identical with it. According to the description, the Mexican species attains a diameter of only 2 mm, and its median chambers decrease in size towards the periphery. Moreover, its surface is described as “recticulate”, which may indicate that the lateral chambers are polygonal like the ones in the small species from Trinidad; on the other hand, it may be that the typical meandric charabers have net yet developed in the small speci- mens from Mexico. This requires further investigation. Holotype.—San Juan, G. 128 °. Localities in San Juan.— G. 128, 153
aye
Distribution in other areas—Paleocene of Soldado Rock and Lizard Springs (Trinidad). Genus PSEUDOPHRAGMINA H. Douvillé Subgenus ATHECOCYCLINA Vaughan and Cole Pseudophragmina (Athecocyclina) cf. cookei (Vaughan) Vaughan and Cole Plate 1, figs. 5, 6; Plate 3, fig. 12; Plate 4, figs. 18, 20 Comp. Discocyclina cookei Vaughan, 1936, Jour. Palcont.. vol. 10. p. 256 i Bs i= ’ be aos Be ct o/— d pl. 42, figs. 1-6. Discocyclina ef. cookei Cole, 1938, Florida Geol. Bulls 16;4p: 31) splaie figs. 4-5, Discocyclina cookei Gravell and Hanna, 1938, Bull. A. A. P. G., vol. 22 pp. 1010, 1012, pl. 7, fig. 7. Pseudophragmina (Athecocyclina) cookei Vaughan and Cole, 1941, Geol. Soc. Am., Special Paper 30, p. 62. ; x ~ . In 1914 Vaughan and Cole introduced the name of Athecocy-
clina for those members of the family of the Discoecvelinde in
J A
d
?
Actually, the hard rock from San Juan is not a favourable material
to furnish the type for this rare species. It would be better to choose the types from loose specimens found at other localities, which would efer more complete information,
365 VENEZUELAN FORAMINIFERA: CAUDRI 15
which the radial walls of the medial chambers are only vaguely indicated or even totally obliterated, so that the median layer shows more or less continuous, mostly rather irregular, unsub- divided concentric rings.
Up to now, data on the few known species of Athecocyclina are scanty. Vaughan and Cole, in describing their new species, A. soldadensis, in 1941, (pp. 25, 63), gave a short comparison with two other forms, A. cookei from the upper part of the Nanafalia formation in Alabama and A. stephensoni from the Chicontepec formation in Mexico, mentioning the ratio between diameter and thickness, the development of pillars and granulations and the shape and number of lateral chambers in vertical section. Loose specimens of A. soldadensis from Soldado Rock and _ Lizard Springs (Trinidad) showed recently that there may be quite a considerable variation both in this ratio and in the ornamentation, so that we may expect difficulties if we try to distinguish the species along those lines. On the other hand, the nature of the lateral chambers, which are rather spacious (12-24 p» high) and arranged in well-marked tiers in A. stephensoni (Vaughan, 1929, Mexico), but low-fissiform (8-12 » high) and irregularly ar- ranged in the two species, seems more promising for systematic purposes. The difference between A. soldadensis and A. cooket would lie chiefly in the number of lateral layers, the former hav- ing only 4-5 layers and the latter as many as 8-9. The specimens from San Juan, having about nine layers overlapping slitlike later- al chambers, would have to be determined as A. cookei, They do not, however, show the peculiar close setting of the radial “plate- like projections” across the rings in the horizontal section, which Vaughan described for that species and which he considered as probably being the remnants of median chamber walls. These plates would be only 15 » apart and the chambers would thus be “very narrow, with the radial diameter as much as four and a half times the transverse diameter’. In our specimens the “me- dian chambers”, as far as they can be distinguished, are approxi- mately square. Careful comparison of the two materials will have to make out whether this is a really important difference or
16 BULLETIN 114 366
whether perhaps a difference in crystallization has to be blamed for it.
Like some Lizard Springs specimens of A. soldadensis, many specimens of A. cf. cookei were observed to have a coarsely papillate surface. They often exceed in this respect the accom- panying Discocyclina aguerreveret, but the papillae do not seem to correspond with equally heavy pillars in the vertical section.
Localities in San Juan.—G,. 41, 9tb, 125c, 128, 153, 164/165.
Distribution outside San Juan.—Alabama, Nanafalia forma- tion; Florida, Salt Mountain limestone, Wilcox group; Texas, Polk County, in a deep well core 8722-8727 feet, age not men- tioned (compare also the distribution in the Paleocene of the very closely related A. soldadensis, Soldado Rock, Trinidad, Barbados).
Genus LEPIDORBITOIDES A. Silvestri Lepidorbitoides cf. planasi M. G. Rutten
Plate 1, fig. 3; Plate 2, fig. 10; Plate 3, fig. 14 Lepidorbitoides planasi M. G. Rutten, 1935, Jour. Paleont., vol. 9, p. 536, pl. 60, figs. 6-7.
The small “orbitoid” that is common in several of the San Juan samples is characterized as a Lepidorbitoides by its extremely fine mesh of thin-walled median chambers and by the spiral de- velopment of its nepionic stage. For the truncated, rounded shape of the median chambers it may be determined as L. planasi Kutten, but the determination must stay provisional until more exact data become available about this Cuban species.
The San Juan specimens correspond well with Rutten’s figures both in horizontal and in vertical sections. They seem, however, different from the Florida material described by Cole (1941), especially in the vertical section. Although Rutten observed that the lateral chambers do not form regular tiers, his figure of the vertical section shows (like the specimens from San Juan) a much stronger tendency to tier formation than Cole’s specimens which have fissiform chambers quite irregularly arranged in horizontal layers (1941, pl. 12, figs. 12-14; 1942, pl. 09, figs. 7-11.).
Rutten did not observe any pillars in his sections, but he ad- mitted that his material was very unsatisfactory. The forms from
367 VENEZUELAN FORAMINIFERA: CAUDRI 1y/
San Juan are variable in this respect but most of them are heay- ily pillared in the center as was observed both in sections and on the weathered surface of the samples.
Localities in San Juan.—G. 41, 91b, 125c, 128, 153, 164/165, Ga Sii Se
Distribution in other areas—Habana formation of Cuba; Pal- eocene blocks at Point Bontour, Trinidad; reworked in upper
Eocene of Point Bontour and Soldado Rock. Lepidorbitoides, sp. ind. ? Plate 3, fig. 16 Among the large amount of L. cf. planasi in G. 125c there are
a few sections in which the median chambers seem to be some- what more pointed ogival, more like a gothic arch. It may be that they represent a different species.
Genus RANIKOTHALIA, n. gen.
jenotype—Nummulites nuttalli (Nuttall, 1926), Davies, 1927.
In 1937 Col. L. M. Davies gave a general review of a peculiar group of nummulitic organisms in the upper Ranikot formation of India, of which Nummulites nuttalli is the central member.
This group is, according to Davies, characterized, in the first place, by the reticulation of the marginal cord and secondly, by the presence of transverse trabecule branching from the septal filaments, which trabecule, however, become apparent only under special conditions of weathering.
The present writer, who, through courtesy of the Sedgwick Museum, had the opportunity to study material of N. nuttalli from its type locality (1934, p. 58, pl. I, fig. 9), would like to add the following characteristics which can be even much more read- ily recognized in most sections because they are independent from the state of preservation:
1. The bluntly rounded chamber tops in horizontal section.
2. The thickness of the coarsely gutted supplementary skele- ton as compared with the majority of other Nummulites.
Both characteristics suggest a close relation of the group to the genus Pellatispira Boussac which, for having a marginal plexus (although much less developed in ordinary nummulites) and a single foramen between adjacent chambers, should be in-
18 BULLETIN 114 368
cluded in the family of the Nummulitidee (Umbgrove, 1928; Bar- ker, 1939, p. 309). Pellatispira, however, has an evolute spiral and a far stronger development of the secondary skeleton and vertical canals than the members of the nuttalli group. On the other hand, the features of this grcup are sufficiently different from those of Nummuulites, s. str. to distinguish it, for conven- ience, as a separate genus, for which I propose the name Raniko- thaha, after the formation (Ranikot) and the locality (Thal), from where it was first adequately described (Davies, 1927).
The Indian representatives of this genus are:
Nummulites nuttali (Nuttall) Davies, con var. kohaticus Da- vies
Nummulites thalicus Davies, con var. gwyne Davies (consid- ered as the megalospheric form of N. xuttalli)
Operculina (or Nummulites) sindensis Davies (1926), 1937
Ranikothalias have also been found in the Caribbean Region and Mexico, from where they were described under various generic names, Operculina, Operculinoides, Camerina, Pella- tispirella, Miscellanea. A short discussion on their nomencla- ture may follow:
In India there occur in the Ranikot beds, side by side with N. nuttalli, c. s., a couple of very similar, strongly granulated forms that were originally described as Nummulites by d’Archiac and Haime (1853) and subsequently by H. Douvillé, Nuttall, Cotter and, at first, also by Davies considered as belonging to Siderolites. As this was not satisfactory, Pfender (Bull. soc. géol. de France, (5), vol. IV, 1934, pp. 225-236, pls. XI-XIII) created the new genus Miscellanea for this kind of organism. They are now known under the name of Miscellanea miscella (d’Archiac and Haime) and Miscellanea stampi (Davies).
Davies (1937, pp. 19-21, 40-42) discussed the relation between his nuttali-group (=Ranikothalia) and Miscellanea. In the lat- ter, the supplementary skeleton is everywhere broken up into pil- lars and, in connection with this, there is no differentiation into compact lateral walls of the shell and a pillared marginal cord (see his text fig. 1). Davies came to the conclusion that Miscel-
S ©
VENEZUELAN FORAMINIFERA: CAUDRI 19
lanea 1s nothing else than a pathologic form of the Nummulites of the nuttali-group, but for practical morphologic reasons he treated it as a separate paleontological genus.
After this was settled, a similar confusion started for the Car- ibbean forms. Here Hanzawa (1937) was the first to distinguish the Jamaican species, Camerina (= Nummulites) matleyi Vaughan from the true Numinwulites on account of the canal sys- tem; he created the genus Pellatispirella for it and described in the same paper also a second species, P. antillea, from Haiti. Vaughan and Cole (1941, p. 32) discussed the validity of this genus and stated that Pellatispirella is a synonym of Miscellanea Pfender. This solution, although firmly based on comparison of the types, does not, however, satisfactorily cover all the details of the problem. There can hardly be any doubt that Pellatispirella matleyt, the genotype, belongs to the same genus as the Indian Miscellaneas, for it shows the peculiar development of the canals which “break up the entire supplementary skeleton into granules” as Davies put it, and it lacks a marginal cord. According to the rule of priority the name “‘Pellatispirella’ has, therefore, to retreat before “Miscellanea’. On the other hand, the second species, P. antillea, though it shows rounded chamber tops and vertical ca- nals like a Miscellanea, definitely possesses a marginal cord and the walls are by no means broken up to the same extent as in P. matleyt or the Indian forms (comp. Vaughan and Cole’s illustra- tions with our figures 21 and 23). Besides, it shows, in accurate equatorial sections, the conspicuous solid lining that separates the chamber cavity from the meshwork of canals in the margin and the thick double septa with a wide interseptal canal enclosed in them (fig. 25; see also Barker, 19309, pl. 20, fig. 10) as we know it from the Nummulites of the nuttalli-group, things that are not found in any of the figures of Miscellanea that I have ever seen, For these reasons, Pellatispirella antillea should be included in the genus Ranikothalia, The same applies to the later described species “Miscellanea” tobleri V. and C. and “Miscellanea” solda- densis V. and C. (figs. 19, 22, 24, 26) and to Operculina bermu- dezi Palmer from the Upper Cretaceous of Cuba (Palmer, 1934,
20 BULLETIN 114 370
p. 238, pl. 12, figs. 3, 6-9; Hanzawa, 1937, p. 115; Thalmann, 1938, 2) 331)| =
The confusion about the generic place of these forms kept Barker (1939) from including Camerina pellatispiroides Barker, n, sp. and Operculinoides catenula (Cushman and Jarvis) in the same group. In my opinion, we can safely consider these species as Ranikothalias; Camerina pellatispiroides seems to be identical with R. antillea and Operculinoides catenula possibly corresponds with our R. toblert (V. and C.)°
The list of Carribbean representatives of the new genus would thus be:
Ranikothalia antillea (Hanzawa) (including Camerina pella-
’
4 The Suleoperculinas (‘‘Camerina’’ dickersoni, cubensis and ver- munti) from the same deposits, of which Mr. 'T. F. Grimsdale kindly gave me some topotype material, do not definitely belong io the genus Ranikoth- alia. (See note 5. The name ‘‘ Sulcoperculina’’ was introduced by Thal- mann, 1938).
5 Operculina catenula Cushman and Jarvis was originally described in 1932 from Lizard Springs, Trinidad, from the same area that also fur- nished the type of Vaughan and Cole’s ‘‘ Miscellanea tobleri’’ (1941). Tis description is very inadequate and can hardly interfere with the validity of the name ‘‘tobleri’’. Should, however, the Mexican species prove to be identical with the Trinidad one, then Barker’s description would pro- cure priority for the name ‘‘catenula’’ over ‘‘ toblerv’’.
Recently, Cole (1942) identified the various Sulcoperculinas from the Cuban Maestrichtian (which he considered as actually belonging to one spe- cies) with both Cushman and Jarvis’s Operculina catenula from Trinidad and Barker’s Operculinoides catenula from Mexico, applying the name ot Miscellanea catenula to the lot. There are serious objections to this gen- eralization. In Thalmann’s subgenus Sulcoperculina the margin has a defi- nite groove which in perfeet specimens may be concealed by its delicately fringed edges but shows up in worn fossils or at least causes the narrow edge of the test to be flattened, and is always very conspicuous in vertical sections. Both the groove and the fringed edges are quite characteristic. Cushman and Jarvis do not give a very clear picture of their Operculina catenula, but both from the description and from their figure 13 it may be understood that the periphery is ‘‘broadly rounded’’. Moreover, as Sulcopereulinas have never been found in Lizard Springs whereas Kani- kothalia has, it seems more probable that the original O. calenula was a Ranikothalia. As for Cole’s identification of the Mexican forms with Sulcoperculina: Barker never stated anything about a groove, but, to the contrary, remarked that his specimens have ‘‘a strongly developed rounded keel’’ and his figure 8 on plate 21 shows a good marginal cord. These forms, too, are rather Ranikothalias than Sulcoperculinas. The Cuban Sulcoperculina stands quite apart, probably as a separate genus, and should not be confused with ‘‘ Miscellanea’’, neither with Ranikothalia wor with true Miscellanea Pfender.
Sal VENEZUELAN FORAMINIFERA: CAUDRI 21
tispiroides Barker)
Ranikothalia toblert (V. and C.) (probably including O pfercul- imoides catenula (Cushman and Jarvis)
Ramkothalia soldadensis (V. and C.)
Rantkothaha bermiudezi (Palmer)
Summarizing, we see that in this peculiar group of the family of the Nummulitidze (== Camerinidz) we can distinguish the fol- lowing genera:
Rantkothalia (nuttalli, thalica, sindensis, antillea, tobleri, sold- adensis, bermudezt) (geographical distribution: India and cen- tral America)
Miscellanea (miscella, stampi, matleyi) (India and central America)
Pellatispira (maderaszi, orbitoidea, rutteni, infata, glabra, ir- regularis, crassicolumnata and others) (southern Europe and Indo-Pacific Region °)
In addition to these there is the still obscure genus Biplanispira (=Heterospira Umbgr., non Koken) (mirabilis, absurda) which is described from Borneo by Umbgrove (1936, 1938).
The close relation between the Indian and the Caribbean rep- resentatives of Ranikothalia accentuates the peculiar correlation between the upper Ranikot formation in India and the base of the Tertiary in the Caribbean Region that was already noted by Vaughan and Cole with reference to the genus Miscellanea (loc. Giles 33):
The detailed description and systematic comparison of the Caribbean species are beyond the scope of the present paper. They cannot be based on specimens in hard rock, but require a careful study of loose material, such as that from Trinidad and Soldado Rock. A short preliminary characterization of the Ter- tiary forms, FR. antillea, tobleri and soldadensis, which are all three present in the limestone from San Juan, will be given, however, below. The Cretaceous species, R. bermudezi, seems to be slight- ly different in having straighter septa in horizontal section.
3 See remark on p. 37,
22 BULLETIN 114 372
Ranikothalia antillea (Hanzawa) Plate 1, figs. 4, 5; Plate 3, fig. 15; Plate 4, fig. 21; Plate 5, figs. 23, 25
/Pellatispira, sp., Gorter and van der Vlerk, 1932, Leidsche Geol. Meded., deel £V, p. 95, pl. 16, fig. 8.
Pellatispirelia antillea Hanzawa, 1937, Jour. Paleont., vol. 11, p. 116, pl. 20 ess SallOls| pl 2h tig. all
Camerina pellatispiroides Barker, 1939, Proe. U. 8. Nat. Mus., vol. 86, Deseo, pln LO tos LO Spls22)mioa,
Miscellanea antillea Vaugian and Cole, 1941, Geol. Soc. Am., Special Paper, No. 30, pp. 24, 33, pl. 4, figs. 1-4; pl. 6, figs. 3, 3a.
Miscellanea, sp. et. M. antillea, loc. cit., pp. 24, 35, pl. 4, figs. 3-4.
€
Miscellanca, sp., robustly lenticular form, loc, cit., p. 25.
Ranikothalia tobleri (Vaughan and Cole) (compare footnote 5) Plate 5, figs, 22526?
? Operculina catenula Cushman and Jarvis, 1932, Proce. U.S. Nat. Mus., vol. 80, p. 42, pl. 12, figs. 13a-b.
Gperculinoides catenula Barker, 1939, Proce. U. 8. Nat. Mus., vol. 86, p. 320, pl. 14, figs. 6, 8; pl. 18; fig..5; pl. 21, figs. 7-8.
Miscellanea tobleri Vaughan and Cole, 1941, Geol. Soc. Am., Special Paper, No: 30; pe 35, pl.r4, figs. 0-7 ple 7s ale
? Miscellanea, sp. cf. M. soldadensis, loc. cit., p. 36, pl. 4, fig. 10
/Misecllanea, sp. compressed lenticular form, loc. cit., p. 25.
Non Miscelianea catenula Cole, 1942, Jour. Paleont., vol. 16, p. 640, pl.
92, figs. 6-10 (seé footnote 5).
Ranikothelic antillea, toblert and soldadeisis are very closely related to each other. /. antillea is a megalospheric form, FR. sol- dadensis is a large microspheric form, and PR. tobleri is somewhat intermediate in size between these two and its original descrip- tion (Vaughan and Cole) comprises both the megalospheric and the microspheric generation.
From the study of detached specimens from Trinidad and Sol- dado Rock, the author got acquainted with the difficulties of sep- arating these species in a satisfactorily objective way. In the extremes, the two types of megalospheric forms, which are far more common than the microspheric ones, may be very different, but in respect to every single characteristic which one tries to use for the distinction of the specimens in a population there is such a confusing variability that even in loose material it is not practicable to assign each individual to either one species or the other, Specific determination is, of course, still more uncertain in hard rock samples and it is better to take the two together in re- cording their occurrence in San Juan. Both types are present ; typical examples of /e. antillea, the robustly lenticular species
373 VENEZUELAN FORAMINIFERA: CAUDRI 23
with a narrow coil and squarish-rounded chambers, are shown in figures 4, 5, 15, 21, 23 and 25, whereas our figures 22 and 26? represent FR. tobleri which is as a rule flatter and has a wider spiral with accordingly higher, slightly curved chambers, the tops of which are more evenly rounded than in the former spe- cies.
Localities in San Juan.—G.41, 86, 91a, gib, 125c, 128, 153, 164/165, G.s.s.
Distribution in other areas:
R. antillea—Cap Haitien, Haiti; upper Lizard Springs beds, Trinidad; Soldado formation on Soldado Rock; Chicontepec formation, Mexico; Misoa-Trujillo formation, Venezuela; Paleo- cene blocks at Point Bontour, Trinidad and (7) those in the Joes River mudflows in Barbados. Reworked in the transgressive upper Eocene of Point Bontour and Soldado Rock.
R. tobleri—Upper Lizard Springs beds, Trinidad, and in blocks in that vicinity; Soldado formation, Soldado Rock; Mex- ico, in beds of doubtful age, perhaps referable to the Chicontepec formation; (/) Paleocene blocks in the Joes River mudflows, Barbados; Paleocene blocks at Point Bontour, Trinidad. ke- worked in the transgressive upper Eocene of Soldado Rock. Ranikothalia soldadensis (Vaughan and Cole)
Plate 4, fig. 19; Plate 5, figs. 24, 26?
EguaesTAn ella, sp.. Hanzawa, 1937, Jour. Paleont., No. 11, p. 116, pl. 21,
ees soldadensis Vaughan and Cole, 1941, Geol. Soc. Am., Special
Paper, No. 30, pp. 24, 25, 36, pl. 4, figs. 8-9.
The original description of this species was based on vertical sections in hard rock from Soldado Rock.
The San Juan limestone contains several specimens of this large flat form, likewise shown as vertical sections or cut in a somewhat obliquely horizontal direction. It is a wide-coiled mic- rospheric form characterized by its particularly well-developed marginal cord. Quite possibly it is identical with the B-form of R. tobleri, representing the adult stage.
Localities in San Juan.—G.41?, 91b, 153, G.s.s. (common).
24 BULLETIN 114 374
Distribution in other areas —Paleocene of Soldado Rock (and reworked in the transgressive upper Eocene there) ; Paleocene blocks in th Joes River mudflows, Barbados; Cap Haitien, Haiti.
“Tubiform odliths” Plate i. fies) ieee
Most of the samples in our collection have a definitely oolithic appearance which shows best on the natural weathered sur- face or after polishing. In thin sections, too, these “‘ooliths” can be very conspicuous. They are of an organic nature but their systematic place can not be determined.
The majority seem to be long, thin structures with a circular cross section; others are perhaps shorter and more or less round- ed, but they all have approximately the same diameter, In many cases they enclose a small fossil (Amphistegina, Rotalia, a fragment of an orbitoid or frequently some remnant of the thallus of Corallina), which shows that at one time they must have been hollow or must have grown round a foreign body, Their wall is as a rule clear and structureless (resorbed in recrystalliz- ation) or sometimes iron-stained and with a definite indication of concentric growth. The filling of their cavities seems to be com- paratively hard, so that in weathering the surface of the rock becomes granular just like in genuine “‘ooliths.”’
Apart from San Juan I have only once met with similar “tubi- form ooliths”, viz., in a highly recrystallized reef limestone from Soldado Rock (K. 3876) which was found as a derived block in Kugler’s upper Eocene “rubble bed’. Lithologically this sam- ple resembles to a certain extent the Paleocene “Discocyclina limestone” (type sample of Athecocyclina soldadensis V. and C.), which also occurred as a block in the basal bed of the trans- gressive upper Eocene of that islet (see Kugler, 1938, p. 216), but it does not contain any larger Foraminifera.
THE AGE OF THE SAN JUAN FAUNA
The question of the age of the San Juan limestone is of con- siderable importance because it doubtless must be placed near the boundary between the Cretaceous and the Tertiary and here again we have to face the problem of the faunal changes
STO VENEZUELAN FORAMINIFERA: CAUDRI 25
that mark the transition from one period to the other and of the value of various forms as index fossils.
Dr. Aguerrevere was so kind as to give us in a letter, dated the 11th February 1941, some details about the local stratigraphy, especially indicating how the sample G.g1, which was the first sample received for investigation, is linked with the impor- tant macrofauna found at this locality as there is no funda- mental lithological or paleontological difference between G.gI and the other samples’, probably applicable to the whole of our “pseudo-oolithic limestone”.
S
G.gi, fossiliferous marl
metamorph
Section 1. The annotation on this section stated that no ammonites were found here but that in the macrofauna there occurred a gastropod that looked like Woodsalia and a large badly preserved ‘‘Inoceramus’’ and also fragments of hinge lines reminding one of Inoceramus. Probably there is not much vertical displacement in the fault between the morro limestone and the marls at Ggi; the morro limestone was believed to be nothing but the reef facies of the same formation which includes the G.91 material and the sediments to the south as far as a certain distance south of the vil- lage of San Juan.
The state of preservation of the “/noceramus” from G. 91 is bad and the “I’oodsalia’” is, according to a tentative determin- ation by W. P. Woodring very similar to the lower Eocene or Paleocene, Turritella mortoni Conrad (comp. Kugler, 1938, p. 205), but if the identification should be correct, the occurrence of these two genera would indicate a Cretaceous age for G.gt and
the “Woodsalia’-Ostrea beds.
7 Neither the sample G.91a nor G.91b contains any Discocyclina, s. str., but as the frequency of this genus varies greatly even in the other sam- ples where it is certainly present, there is no reason why this absence should be particularly emphasized.
26 BULLETIN 114 376
W 2
beds with”"Woodsalia” & Ostrea-bank
bed with Ammonites
chlorite schists
Section 2.—From the field relations the zone ineluding the sediments from the morro limestone down to the shale, which contains, on the east face, the beds with ‘‘ Woodsalia’’ and the Ostrea bank, seemed to be con- temperaneous with the section at G.91 but the ammonites and Acteon- ellas come from a lower horizon. On the west slope of section 2 the am-
a
monite beds were thought to be in fault contact with the neighboring lithology, the material at G.91 being, in all probability, younger than the ammonite beds.
From this we see that the age of our material, although it is considered as vounger than the ammonite-bearing horizon, has nevertheless, for 1ts mollusc contents, perhaps to be determined as Cretaceous, On the other hand, the microfauna shows too much affinity to the Tertiary to corroborate that conclusion.
Summarizing, the following seven species of larger Foramini- fera have been found in our collection:
Discocyclina aquerreverei, n. sp. (closely related to D. grims- dalei V. and C.)
Athecocyclina cf. cookei Vaughan (closely related to A. sol- dadensis V. and C.)
Hexagonocyclina meandrica, n. sp. (very closely related to Discocyclina cristensis Vaughan)
Lepidorbitoides cf. planasi M. G. Rutten (specific determina- tion probably correct)
Ranikothalia antillea (Hanz.) (Miscellanea antillea (Hanz.) in Vaughan and Cole, 1941)
377 VENEZUELAN FORAMINIFERA: CAUDRI 27
Ranikothalia tobleri (V. and C.) (=Miscellanea tobleri V. and C.)
Ranikothalia soldadensis (V. and C.) (=Miscellanea soldad- ensis V. and C.)
In order to obtain an idea about the relative age of this fauna we have to compare it with the following faunze from this same region (Caribbean and around the Gulf of Mexico) :
1. Upper Scotland formation (Murphys beds, Chalky Mount beds and Mount All beds), Barbados
Age: Between Paleocene and upper Eocene; according to Senn (1940), Renz (1942) and Vaughan (1942) ; middle Eocene
According to rough preliminary determinations made by Senn (loc. cit., pp. 1554-1560) :
Discocyclina, s. str. Asterocyclina Nummulites O perculina Amphistegina cf. lopeztrigot Palmer 2. Nanafalia formation, upper part, Alabama Age: Lower Eocene (Vaughan, 1936; Vaughan and Cole, 1941, p. 63) Discocyclina blanpiedi Vaughan Athecocyclina cookei (Vaughan 3. Salt Mountain limestone, Florida Age: Lower Eocene (Wilcox group) (Cole, 1938) Athecocyclina cf. cookei (Vaughan) 4. Chicontepec formation, Mexico Age: Lower Eocene (Vaughan, 1929; Barker, 1939) Discocyclina weavert Vaughan -. Discocyclina weaveri var. parvipapillata Vaughan Hexagonocyclina cristensis (Vaughan) Athecocyclina stephensoni Vaughan Ranikothalia antillea (Hanz.) (see Barker, 1939; Camerina pellatispiroides, n. sp.) Ranikothalia (?) tobleri (V. and C.) (see Barker, 1939: Operculinoides catenula (Cushman and Jarvis) )
28 BULLETIN 114 378
s. Soldado Rock, off Trinidad, B. W. I, samples K. 2950 and K. 2951; type locality of the Paleocene (Soldado formation) in the central American region Age: Paleocene, lower Eocene (Kugler, 1938; Vaughan and Cole, 1941) Discocyclina grimsdalet V. and C. Discocyclina barkeri V. and C. Discocyclina aguerreveret, Nn. sp. Discocyclina “crassa (as figured by Vaughan and Cole, LOATH pl, 2O.0tes. 10,57.) Hexagonocyclina meandrica, n. sp. Hexagonocyclina, n. sp. (different species) Athecocyclina soldadensis V. and C., Ranikothalia antillea (Hanz.) Ranikothalia tobleri (V. and C.) Ranikothalia soldadensis (V. and C.)
Notes.—The so-called “Discocyclina limestone’, a Paleocene algal reef found as scattered blocks in the overlying upper Eo- cene deposits of this islet, contains:
Athecocyclina soldadensis V. and C, (abundant)
Discocyclina aqguerreverel, n. sp. (extremely rare)
Among the numerous reworked Paleocene Foraminifera con- tained in the transgressive upper Eocene “rubble bed” (K. 2951B) one specimen of Lepidorbitoides cf. planasi was found, which suggests that this species must be present in the Soldado formation, although up to now not observed in place.
One of the samples collected on Soldado Rock is a limestone entirely built up by “tubiform ooliths”. The presence of this kind of rock in a place, where up to now no pre-Tertiary de- posits have been found, is perhaps worth while mentioning al- though no premature conclusions should be drawn from it.
6. Lizard Springs beds, upper part. Type locality, Ravine Ampelu, Lizard Springs area, SE. Trinidad, B.W.I.
Age: Lower Paleocene (Renz, 1942, p. 531)
Discocyclina, sp. (closely related to D. barkeri V. and C.) Discocyclina grimsdalet V. and C.
379 VENEZUELAN FORAMINIFERA: CAUDRI 29
Discocyclina “crassa” (as figured by Vaughan and Cole, 1941, pl. 20, figs. 6, 7)
Discocyclina aguerreverei, n. sp.
Hexagonocyclina meandrica, n. sp.
Athecocyclina soldadensis V. and C.
Ramntkothalia antillea (Hanz.)
Ranikothalia tobleri (V. and C.)
Ranikothalia ? soldadensis (V. and C.)
Note.—Viaughan and Cole’s type material of Miscellanea tob- leri (Lizard Springs, M.12) should, in comparison with this fauna, also be considered as of Paleocene age, although it does not come from exactly the same locality. Possibly it was found as reworked material in a surrounding of younger deposits. It
is accompanied by Discocyclina “crassa”. 7. Paleocene algal reef limestone blocks at Point Bontour, near San Fernando, Trinidad, B.W.I. (Renz, 1942, p. 535) Discocyclina grimsdalei V. and C. Discocyclina “crassa” (as figured by Vaughan and Cole, LOAT, pl. 2O-f1sSt 6, 7) Discocyclina aquerreveret, n. sp. Athecocyclina soldadensis V. and C. Hexagonocyclina meandrica, n. sp. Hexagonocyclina, n. sp. (different species, same as in Sold- ado Rock) Lepidorbitoides cf. planast M. G. Rutten Rantkothalia antillea (Hanz.) 8. Paleocene grit blocks embedded in the Joes River mudflows, Barbados. (Senn, 1940, p. 1574; Vaughan and Cole, 1941, p. 25; Renz, 1942, p)1535) Ranikothalia, sp., robustley lenticular form (RF. antillea?) Rantkothalia, sp., compressed lenticular form (FR. tobleri?) Rantkothahia soldadensis (V. and C.) Discocyclina, sp., aspect of D. barkeri V. and C. Discocyclina, sp., apparently D. grimsdalei V. and C. Athecocyclina soldadensis V. and C. Norte.—Senn’s preliminary generic determination was: Disco-
30 BULLETIN 114
cyclina (Discocyclina), Nummulites and Operculina. g. Cardenas beds, Mexico Age: Upper Cretaceous (Maestrichtian) Barker and dales 10377 Barker, 1930) ’Camerina (Sulcoperculina) dickersoni Palmer*) Borelis cardenasensis B. and Gr. Lepidorbitoides minima H. Douv. ?Meandropsina ruttem Palmer (Vaughanina in equivalent deposit elsewhere) 10. Habana formation, Cuba
380
Grims-
Age: Upper Cretaceous (Maestrichtian) (Palmer, 1934; M. G. Rutten, 1935, 1936; Thiadens, 1937, both papers; Vermunt,
1937; Voorwijk, 1937) Orbitoides browni (Ellis) Orbitoides palmert Gravell Orbitoides apiculata Schumb. Lepidorbitoides (Lepidorbitoides) minima H. Douv.
Lepidorbitoides (Lepidorbitoides) planasi M. G. Rutten
Lepidorbitoides (Lepidorbitoides) ruttent Thiadens
Lepidorbitoides (Lepidorbitoides) ruttent var. armata Thi-
adens Lepidorbitoides (Lepidorbitoides) palmeri Thiadens
Lepidorbitoides (Lepidorbitoides) macgillavryi Thiadens
Lepidorbitoides (Cryptasterorbis) cubensis (Palicr) Lepidorbitoides (Asterorbis) aquayot Palmer Lepidorbitoides (Asterorbis) rooki V. and C, Lepidorbitoides (? Asterorbis) macci Palmer Lepidorbitoides (2? Asterorbis) havanensis Palmer Pseudorbitoides tsraelskii V. and C. Pseudorbitoides trechmanni H. Douville Vaughanina cubensis Palmer
Omphalocyclus macropora Brown
Omphalocyclus, sp. ind.
Torreina torret Palmer
?Meandropsina rutteni Palmer
See notes 4 and 5.
381 VENEZUELAN FORAMINIFERA: CAUDRI 31
?Camerina (Sulcoperculina) dickersoni Palmer* ?Camerina (Sulcoperculina) cubensis Palmer ?Camerina (Sulcoperculina) vermunti Thiadens Operculina (Ranikothalia) bermudezi Palmer
The above leaves no doubt as to the very close relationship be- tween the San Juan fauna and the faunz of the Soldado forma- tion and its equivalents (Soldado Rock, Lizard Springs, Point Bontour block, Joes River mudflow block, Chicontepec forma- tion in Mexico), but there is also a strong resemblance to the lower Eocene in Alabama and Florida and even to the middle (?) Eocene of Barbados, although it is striking that San Juan is lacking exactly in those forms that give the latter deposit its post-Paleocene appearance.
With the Maestrichtian of Cuba the similarity seems to be far less. It is true that the two faunze have Lepidorbitoides planasi in common, while Operculina bermudezi is, if not iden- tical, at any rate very closely related to the microspheric Rani- kothalias we find in San Juan. But the general character is en- tirely different. The common and conspicuous Cretaceous forms like for instance Asterorbis and Vaughanina are completely ab- sent in San Juan, and Discocyclina and Athecocyclina are not represented in the Habana formation.
So, although there are certain slight differences if the San Juan limestone is compared in detail with the classic Soldado Rock locality®, there can, in my opinion, be no doubt that this
limestone is of the same age as the Soldado formation”.
9 These differences are: 1. The absence of small Discocycline of the group of D. barkeri 2. The abundance of Lepidorbitoides 3. The presence of D. aguerreverei instead of D. grimsdalei 4. The presence of Athecocyclina ef. cookei instead of A. soldadensis.The striking abundance of Athecocyclina can be explained by the facies. This genus seems to prefer compact algal reefs (comp. the ‘‘ Discocyclina limestone’’ on Soldado Rock and the reef limestone block at Point. Bontour).
10 This is not necessarily the age of ‘the formation that is exposed at the localities from whence the samples were collected. In the stratigraphical notes and sections Dr. Aguerrevere sent us, this information is,at G.91,called a ‘‘fossiliferous marl’’, whereas the sample G.91 was, like the rest, a hard limestone. Although the samples do not have the appearance of boulders, it should be kept in mind that there is a possibility that the limestone oe- curs at these localities as reworked material in a younger formation.
32 BULLETIN 114 382
THE CORRECT STRAMGRAPHICGALN PLACE FGPh, fie SOLDADO FORMATION
There has been a controversy about the correct designation of the Paleocene, a discussion of which can be found in papers by Barker (1936, p. 443), Rutsch (1939) and Vaughan and Cole (1941, p. 25). Some authors include the Paleocene in the Eo- cene as its lowermost member, but it seems to be more common- ly accepted (e. g., by the Committee on Geologic Names of the U. S. Geological Survey) that the Paleocene should be given the rank of a separate epoch preceding the Eocene. In the latter case there is, however, no complete uniformity of opinion as to where the boundary between Paleocene and lower Eocene should be drawn and there is some discrepancy between the use of the term in European and in American stratigraphy. For that rea- son Vaughan and Cole prefer to leave the question undecided and to speak in general of “lower Eocene” for all these deposits, in- cluding the Soldado formation as well as the Nanafalia forma- tion or the Mexican Chicontepec. On the other hand, they ad- mit that the Midway group would in any case belong to the Paleo- cene, As the Soldado formation was on account of many species of molluses determined by Maury as the equivalent of the Mid- way Eocene of Mississippi and the Clayton of Alabama (see Kugler, 1938, p. 204 (3), it seems logical to mark down the Sol- dado formation as Paleocene. The same applies to the Chicon- tepec formation (Barker, 1936, p. 443), to the upper part of the Lizard Springs beds (Renz, 1942, p. 531 and table), the tauna in the blocks of the Joes River mudflows (Vaughan and Cole, 1941, p. 25) and, consequently, that of San Juan.
Turning to another aspect of the question, we have to decide whether this American Paleocene (Midway) belongs to the Ter- tiary or whether it forms part of the Cretaceous. In general, it was always considered as Tertiary, but in recent years some doubt was expressed here and there. A thorough discussion of the sub- ject has been given by Fox and Ross (1942, p. 672) in connec- tion with the age of the Cannonball formation in North Dakota.
383 VENEZUELAN [‘ORAMINIFERA: CAUDRI 33
Their conclusion was that the Midway belongs to the Tertiary and not to the Cretaceous.
One of the data which evokes this doubt is offered by the mol- luse fauna of the San juan material itself, as has been cited above (p. 26). Not being specialized in molluscs, the author does not feel competent to take part in the discussion from that point of view, but judging from the larger Foraminifera there are cer- tainly more arguments in favor of a Tertiary than of a Cretaceous age. There is far less resemblance between the Paleocene faunas and that of the Cuban Maestrichtian than there is between the Paleocene and the lower and middle Eocene. But what seems to me the strongest argument of all is that all the Paleocene (and “lower Eocene’) localities mentioned above have yielded true Discocyclina, s. str., for in spite of all the statements in literature about the find of so-called “Cretaceous Discocyline” there are up to now no unchallengeable data about the first appearance of that genus earlier than in the Tertiary (see Caudri, 1937).
PEE VER TIiCMe DISTRIBUTION OF THE UPPER CRE TACEOUS AND LOWER TERTIARY LARGER FOR- AMINIFERA IN THE REGION AROUND THE CARIBBEAN AND THE GULF OF MEXICO
The San Juan fauna is a striking example of the overlap of the vertical range of Lepidorbitoides, which was up to now generally considered as typical of the Cretaceous, and such Tertiary forms as Discocyclina and Athecocyclina, a phenomenon which has lately been noted at several other localities as well.
The position of such faunz is highly important from a strati- graphic point of view and, although we need many more data be- fore we can arrive at a final conclusion, a first attempt has, therefore, been made here to disentangle the problem by listing the Cretaceous and lower Tertiary faunz of larger Foraminifera in this region and combining them into a tentative distribution chart.
This chart by no means claims to represent the condensa-
tion of established knowledge of the vertical range of the various
By! BULLETIN 114 384
forms mentioned in it. First of all, it 1s incomplete because I had not access to all the literature on the subject (e. g., all the papers by Douvillé, many of those by Cushman and the earlier ones by Vaughan are left out) ; second, the exact stratigraphic position of several of the localities is still uncertain; and third, reworking may have had its influence in more than one case where we find a somewhat astonishing assemblage. The chart is, therefore, meant only as a summary of my present informa- tion and as a guide for further investigation.
ANNOTATIONS TO THE TENTATIVE DISTRIBUTION CHART
1. LITERATURE The following publications were used in the compilation of our
chart: V enezuela—Gorter and Van der Vierk, 1932; Gravel) "19337;"Senn, 1935 Trinidad and Soldado Rock—Cushman and _ Jarvis, 1932; Kugler, 1938; Vaughan and Cole, 1941; Renz, 1942. Barbados—Senn, 1940; Vaughan and Cole, 1941; Vaughan, 1942; Renz, 1942, Jamaica—Vaughan, 1928, 1929. Haiti—Hanzawa, 1937. Cuba—Cushman, 1919, 1919, (1920) ; Palmer, .1934;-M. G. Rutten, 1935, 1936; Thiadens, 1937, both papers; Vermunt, 1937; Voorwijk, 1937 Florida—Cushman, 1919, (1920); Cole and -Ponton, 1934; Cole, 1938, 1941, 1942; Gravell and Hanna, 1938. Alabama—Vaughan, 1936; Gravell and Hanna, 1938. Mississip pi—Gravell and Hanna, 1938, 1940. (Louisiana)—Vaughan, 1936 Mexico—Cole, 1927; Vaughan, 1929; Barker and Grimsdale, 1936, 1937; Barker, 1936, 1939; Senn, 1940 (p. 1559).
( ~~, le , Fa!
LOWER TERTIARY UPPER CRETACEOUS
- ceaahti : eeuie: Middle Koce : ~ Upper Eocene . | cis) |e chr | ae TENTATIVE DISTRIBUTION CHART . ey
: ICA FLORIDA Mexico Trinipan & Cusa FLorwwa Froripa Cusa _ Sotpano Rock ALABAMA FLoripa BARBADOS JAMA "s
Mexico OF THE
Habana Solilado form. Nanafalia Lower (and epee Sotpapo Rock Le nn 5, i i Eocene Gi ba ; i UPPER CRETACEOUS AND LOWER TERTIARY Se eee a. i Se formation Upper “* Yellow Mississippi) formation Mount Moriah
i idle lt ‘ & equivalents _ Lizard Springs (upper part) (e. ge limestone’’ RG ; si JAMAICA Louisiana) LARGER FORAMINIFERA = : Mexico beds Salt Mountain Scotland Eocene Claiborne
formation VENEZUELA limestone) VENEZUELA ‘* Lower Ocala IN THE CARIBBEAN REGION AND CArdenas 8. Juan limestone formation
Cerro Campana White limestone limestone and limestone’’ beds BarBabos
a. Ri * & equivalents Blocks in Joes Sta. Rita a AROUND THE GULF OF MEXICO Seinen
conglomerate
Tantoyuca
& equivalents
Haiti. (Cap Haitien) Mexico Chicontepee form
Menegranile
Asterorbis (+ Cry ptasterorbis)
Lepidorbitoides, s. str. (Orbitocyclina)
Orbitoides, s. str.
Pseudorbitoides
Vaughanina
Omphalocyclus
Torreina
?Meandropsina rutteni
Sulcoperculina
Ranikothalia
Borelis
Hexagonocyclina
Athecocyclina
Discocyclina, s. str.
Proporocyclina
Asterocyelina
Amphistegina lopeztrigoi
Miscellanea
Dictyoconus
“Discocyclina” advena
Helicostegina gyralis & dimorpha (+ Helico- lepidina polygyralis)
Eulinderina
Polylepidina
Lepidocyclina claihornensis, cedarkeysensis, and other primitive forms
Operculinpides
Nummulites (Camerina), s. str.
Fabularia
Coskinolina
Gunteria
Pseudolepidina
Operculina, s. str. (complanate type)
Helicostegina soldadensis
Helicolepidina spiralis, c. s.
Lepidocyclina pustulosa, c. s.
Heterostegina
Pseudophraymina floridana
Lepidoeyclina. younger type than L. pustulosa (L, subglosa, c. s,, undosa, c. s., supera, etc.)
Helicolepidina paucispira
385 VENEZUELAN FORAMINIFERA: CAUDRI 35
THE PROBLEM OF REWORKING
a. Discocyclina, s. str.—At present I am under the impression that Discocyclina, s. str. is, at least in the Caribbean Region, not a normal constituent of the upper Eocene fauna. There are sev- eral finds of Discocyclina in the upper Eocene on record but most of them have been determined previous to Vaughan and Cole’s review of the family of the Discocyclinide (1941, p. 57) and re- fer either to Proporocyclina or Asterocyclina (Cushman, 1919, 1919 (1920) ; Gorter and Van der Vlerk, 1932; Vaughan, 1927; Barker, 19360).
As far as Trinidad and Soldado Rock are concerned true Dis- cocycline have actually been found in upper Eocene deposits on several occasions but it is remarkable that they represent, with the exception of one case, exactly the same four or five species that are constant and abundant constituents of the Paleocene faune in the neighborhood and that other Paleocene genera (e. g., Hexagonocyclina, Ranikothalia) are mostly also found in the same deposits, which in many cases show a definitely transgress- ive character (“rubble bed” on Soldado Rock, marl beds with Paleocene blocks and small fragments of limestones at Point Bon- tour, etc.). There is reason to assume that these specimens are all derived from the Paleocene.
The exception referred to is the fauna of the limestone K. 3878, mentioned by Vaughan and Cole. This sample, which was col- lected on Soldado Rock from a horizon slightly above the very rich beds containing a typical Mount Moriah fauna, yielded a pure assemblage of Discocyclina (Discocyclina) bullbrooki V. and C., n. sp. and Pseudophragmina (Proporcyclina) tobleri V. and C., n. sp., together with some probably also new Amphist- egine. These larger Foraminifera have nothing in common eith- er with the Paleocene or the typical upper Eocene of this very small islet, but their general character seems old: the Discocyclina is very similar to the Paleocene species and the Proporocyclina is more primitive than the species found in the underlying upper Eocene beds. The fauna of smaller Foraminifera, which was studied by H. H. Renz, has several species in common with the
36 BULLETIN 114 356
typical Soldado Paleocene ''. From a paleontological point of view it is highly improbable that this peculiar fauna should suc- ceed the rich Mount Moriah fauna in normal sequence and the most acceptable explanation seems to be that it originated from a high-Paleocene (or perhaps lower or middle (7?) Eocene) marl that was up to now never found im situ at this locality, and that it was re-deposited as a whole in a high, in itself barren, trans- gression niveau of the upper Eocene (Kugler’s bed 11). Scat- tered specimens from this fauna are also found mixed with the upper Eocene fauna in the immediate neighborhood, especially in the upper part of the underlying bed 10 (e. g., K. 3691, 3692).
Among the “upper Eocene’ Discocyclinz of the older liter- ature (Cushman) only Orthophragmina marginata from S. Bar- tholomew and O, crassa and cubensis from Cuba may be true Discocyclinz, but the descriptions are very unsatisfactory. The age of the S. Bartholomew deposit is doubtful (see p. 39). As to the Cuban species, the comprehensive fauna listed from the upper Eocene of this island shows such a peculiar mixture of characters (Dictyoconus, Oligocene-like Lepidocyclinz, usually large Nummutlites) that we can not dismiss the thought of the possibility of reworking without a careful revision of the individ- ual fauna of each locality. D. crassa is also mentioned from the lower White Limestone of Jamaica (Vjaughan, 1928), where it is found likewise in association with Dictyoconus.
For the above reasons, the range of Discocyclina, s. str. was tentatively not extended in the chart beyond the middle-upper Eocene boundary.
b. Hexagonocyclina—Like Discocylina, this genus is consid-
11 Dr. Renz kindly gave me the following information on the smaller Foraminifera: Sample K.3878, Soldado Rock, contains the following Fora- minifera which are also present in the type sample, Pulvinulinella obtusa (Burrows and Holland), Quinqueloculina, sp., Hponides elevata (Plam- mer), Anomalina, sp., Robulus, sp., Gyroidina subangulata Plummer Cibicides praecursorius (Sehwager). Others are too badly preserved (re-
erystallized) to be determined specifically. (Comp. Cushman and Renz, 1942)
387 VENEZUELAN FORAMINIFERA: CAUDRI 37
ered as reworked when found in upper Eocene deposits.
c. Lepidorbitoides—The overlap of this genus over the boun- dary between the Cretaceous and the Tertiary seems for the mo- ment rather unchallengeable. The slightly breccious appearance of some of the San Juan samples (autoclastic breccia?) is not enough reason to suspect reworking and the presence of Lepid- orbitoides in the algal reef at Point Bontour (block) seems per- fectly normal (see p. 29).
d. Ranikothalia—This genus is, for the time being, regarded as ranging from the Upper Cretaceous (Habana formation, Cuba) to the Paleocene or perhaps somewhat higher, but the specimens reported from the upper Eocene are considered as reworked for the same reasons that were given in connection with Discocy- clina, s. str. Special attention should be paid, however, to the fact that the type locality of FR. antillea (Cap Haitien, Haiti) is mentioned by Vaughan and Cole (1914) as supposedly of upper Eocene age (p. 33). Apart from that species, the locality yield- ed also R. soldadensis (loc. cit., p. 36) and the authors admit “that the limestone from which the specimens were taken may belong to the lower Eocene.” (Loc. cit., p. 24). This record is, therefore, tentatively included in the Paleocene column of our chart, but it may be that this age determination does not apply to
the locality as such (block °, reworked specimens /). 3. ODD REMARKS a. Pellatispira in the American Tertiary.—A vertical section
in a sample from the lower part of the Misoa-Trujillo formation in central Falcon, Venezuela, was determined by Gorter and Van der Wlerk as “? Pellatispira, sp.” (1932, p. 95, pl. 16, fig. 8). Most probably this is a specimen of Rantkothalia, sp. (cf. antil- lea). Up to now, the genus Pellatispira has not been found in the New World.
b. Nummulites and Operculina in Barbados.—Senn (1940) included these two genera tentatively in the faunze from the Pale- ocene blocks in the Joes River mudflows (p. 1574) and from the
38 BULLETIN 114 388
upper Scotland formation (p. 1554, 1556, 1559), whereas he also mentioned a “Nummulites’ from the lower Scotland formation which is supposed to be the lower Eocene age (p. 1553). On locking through material collected at his type localities I found that the only Nummulitide in these samples were Ranikothalias and, as Senn’s faunal lists are based only on preliminary field determinations, | did, therefore, not insert the Barbados Num- mulites and O perculina in the chart..
From this there appears to be a possibility that the range of Ranikothalia reaches as high as middle Eocene, but this ques- tion is left out of the discussion for the present.
c. Spiroclypeus in the upper Eocene——The only data about the
i
f
occurrence of Spiroclypeus in the American upper Eocene are given by Gorter and Van der Vlerk, who mention it from the Menegrande beds in central Falcon, Venezuela (1932, pp. 98, 99). The generic determination of the fossils in question seems doubtful. The figure, given to illustrate the find, shows a vertical section that just as well might represent the central part of a Helicolepidina spiralis (pl. 16, fig. 7). As far as America is concerned, Spiroclypeus characterizes, for the moment, a high horizon in the Oligocene and is left out, therefore, of the chart.
d. Heterostegina—Well-developed Heterostegine have been found in the upper Eocene of Cuba and Florida, but for the rest, the genus seems to have its main distribution in the Oligocene in America. ‘The dotted line in the upper Eocene column of Trini- dad refers to a precursory form, morphologically closely resem- bling the Recent species H. operculinoides in the Indo-Pacific Xegion (Hofker, The Foraminifera of the Siboga Expedition, part I, Amsterdam, 1937). It is a very primitive form without secondary septa, in wnich, however, the tendency to subdivison of the operculine chambers is indicated by short secondary canals branching from the interseptal canals at regular intervals.
e. Helicostegina dimorpha, Polylepidina, Lepidocyclina aft. cedarkeysensis and Operculina, s. str. have recently been found in the Mount Moriah silt near San Fernando, Trinidad (unpub- lished data).
389 VENEZUELAN FORAMINIFERA: CAUDRI 39
f. Helicolepidina spiralis—Vhis species is known from Vene- zuela, Trinidad and Soldado Rock, Cuba and Mexico, but up to now not from the southern United States. From Louisiana, how- ever, Vaughan described a very closely related species, H. nor- toni (1936). Its age is probably upper Eocene. The dotted line in the Florida upper Eocene column refers to this find,
g. Lepidocyclina in the pre-jacksonian.—From the middle Eocene two species of Lepidocyclina (not Polylepidina) are re- corded, L. claibornensis Gravell and Hanna from Mississippi and L. cedarkeysensis Cole from Florida, both of which show in sev- erai features a less advanced character than the variable group of L. pustulosa H. Douv., which also includes L. “trinitatis’ (see Vaughan and Cole, 1941, pp. 64-66). However, Gorter and Van der Vlerk (1932, p. 95) mention L. cf. trinitatis from a low hor- izon in the Misoa-Trujillo formation in central Falcon, Venezuela, This horizon is considered by Senn (1935, p. 57) as the base of the middle Eocene; Renz (1942, p. 533) mentions the fauna un- der “Paleocene and lower Eocene”. As this find seems abnormai as compared with the generally accepted upper Eocene age ci the species, this determination should be carefully checked. The record is tentatively left out of the chart.
h. Dictyoconus in the upper Eocene.—Apart from Cuba and Jamaica, Dictyoconus has been recorded from only one locality, the age of which is mentioned as upper Eocene, the Menegrande beds on the shores of Lake Maracaibo, Venezuela (Gorter and Van der Vlerk, 1932, p. 98). It forms part of Tobler’s Rio San Pedro fauna (comp. Senn, 1935, p. 58). Furthermore it has been found in the St. Bartholomew (St. Barthélomy) in the Lesser Antilles, which deposit is considered by Senn as the lower part of the upper Eocene, by others, however, as middle Eocene (see Senn, 1940, p. 1593, 1581). There is still a great deal of uncer- tainty around the exact range of this genus, but its main distri- bution seems, at any rate, to lie in the middle Eocene.
i. Meaning of the abbreviation “c.s.”—The abbreviation “c.s.” (lat.: con sorte) is used in the chart to indicate a group of very
40 BULLETIN 114 390
closely related or in part perhaps identical species (e.g., Helico- lepidina spiralis and H. nortoni, Lepidocyclina pustulosa, L. trin- itatis, L. tobleri, etc., Lepidocyclina subglobosa and L. yurna- gunensis, Lepidocyclina undosa, L. favosa, etc.).
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Barker, R. W.
1930. Micropaleontology in Mexico with special reference to the Tampvtco Embayment. Bull. Am. Ass. Petr. Geologists, vol. 20, pp. 433-456.
1939. Species of the foraminiferal family Camerinide in the Tertiary and Cretaceous of Mexico. Proce. U. 8. Nat. Mus., vol. 86, pp. 305-330, pls. 11-22.
Barker, R. W., and Grimsdale, T. F.
1936. A contribution to the phylogeny of the orbitoidal Foraminifera with description of new forms from the Eocene of Meaxico. Jour. Paleont., vol. 10, pp. 231-247, pl. 30-38.
1937. Studies of Mexican fossil Foraminifera, Ann. and Mag. Nat. Hist., ser. 10, vol. XIX, pp. 161-178, pls. X-IX.
Caudri, C. M. B.
1934. Tertiary deposits of Soemba. Dissertation Leyden, pp. 1-223, plist IeVe
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Cizancourt, H. de
1938. Remarques sur le genre Orbitocyclina Vaughan. Bull. Soe. Geol. de Franee, 5e série, Tome VIII, pp. 645-052, pl. XX XVIII.
Cole, W. 8S.
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1938. Stratigraphy and micropaleontology of two deep wells in Florida. Geol. Bull. State of Florida, Dept. of Conservation, No. 16, pp. 1-73, pls. 1-12.
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1919. Fossil Foraminifera from the West Indies. Carn. Inst. Washing- ton, publ. 291, pp. 21-71, pls. 1-15, 8 text figs.
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391 VENEZUELAN FORAMINIFERA: CAUDRI 41
Cushman, J. A., and Jarvis, P. W.
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1942. Foraminiferal evidence for the Midway (Paleocene) age of the Cannonball formation in North Dakota, Jour. Paleont., vol. 16, pp. 660- 673, 5 text figs.
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1932. Larger Foraminifera from central Falcén, Venezwela. Leidsehe
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1938. Subsurface Tertiary zones of correlation through Mississippi, Ala- bama and Florida. Bull. Am. Ass. Petr. Geologists, vol. 22, pp. 984- 1013, 7 plates.
1940. New larger Foraminifera from the Claiborne of Mississippi. Jour. Paleont., vol. 14, pp. 412-416, pl. 57.
Hanzawa, S.
1937. Notes on some interesting Cretaceous and Tertiary Foraminifera
from the West-Indies. Jour. Paleont., vol. 11, pp. 110-117, pl. 20-21. Kugler, H. G.
1938. The Eocene of the Soldado Rock near Trinidad. Boletin de Geol- ogia y Mineria, Ministerio de Fomento, Venezuela, vol. II, No. 2-4, pp. 202-225 (English edition pp. 1-24), 2 plates, 1 map, 1 plate of cross sections.
Nuttall, W. F. L.
1926. The larger Foraminifera of the upper Ranikot series of Sind.
Geol. Mag. London, vol. LXIII, pp. 112-121, pls. X-XT. Palmer, Dorothy K.
1934. Some large fossil Foraminifera from Cuba. Mem. Soe. Cubana
Hist. Nat., vol. 8, pp. 235-264, pls. 12-16. Renz, H. H.
1942. Stratigraphy of northern South America, Trinidad and Barbados. Proc. 8th American Scientific Congress, 1940, Geological Sciences, vol. 4, General Geology, pp. 513-571, 1 correlation chart.
Rutsch, R.
1939. Die Abtrennung des Paleocdns vom Eocdn. Eclog. geog. Helv., vol.
32, pp. 211-214. Rutten, M. G.
1935. Larger Foraminifera of northern Santa Clara Province, Cuba.
Jour. Paleont., vol. 9, pp. 527-545, pls. 59-62.
43 aa BULLETIN 114 392
1936. Geology of the northern part of the Province of Santa Ciara, Cuba. Dee eek ela Utreekt, (also: Geegraphise: en Geologische Mededee- lngen, Physi ographise! igeologische reeks, No. 11, Utreeht.
1940. On Lepidorbitoides and Driatoey cine Geologie en Mijnbouw, jaarg. I, pp. 263-266.
Bee A. 935. Die stratigraphische Verbreituny der tertidren Grbilciden, nite specieller Beriicksichtiguna ihres Vorkemmens in Nord-Vercezucla wnd Nord-Marokko. FEelog. geol. Helv., vol. 28, pp. 51-113, 369-373, pls. VIII-IX.
1940. Paleogene of Barhados and its bearing on history and structure of Antillean-Caribocan Region. Bull, Am. Ass. Petr. Geeiogists, vel. 24, pp. 1548-1610, 4 jpiates.
Tan, Sin Hok
1935. Die peri-embryonalen Acquatorialkammerin bet einigen Oriifoiden. De Ingenieur in Nederl.-Indié. IV, Mijnbouw en Geologie, jaarg. 2, pp. 113-126.
1939. On Polylepidina, Orbitocyclina and Lepidorbitoides. De Ingenieur in Nederi.-Indei. IV, Mijwbouw en Geologie, ‘‘De Mijningenieur’’ jaarg. 6, pp. 53-84, pl. I-11.
Thalmann, H. E.
1938. Bemerkungen cur Frage des Vorkommens kretazischer Numavat-
iten. Eelog. geol. Helv., vol. 51, pp. 327-333. Thiadens, A. A.
1937. Cretaceous and Tertiary Foraminifera from southern Santa Clara Province, Cuba. Jour. Paleont., vol. 11, pp. 91-109, pls. 15-19, 3 text figs
1937. Geology of the southern part of the Province Santa Clara, Cuba. Dissertation Utrecht, (also: Geographische en Geologische Mededee- lingen, Physiographischegeologische reeks, No. 12, Utrecht, 1937).
Umbgreve, J. H. F.
1928. Het genus Pellatispira in het Indo-pacifische Gebied (with sum- mary in English). Wetensch. Mededeelingen v. d. Dienst v. d. Mijn- bouw in Nederl.-Ind?é, Ne. 10, pp. 1-60, figs. 1-80.
1936. Heterospira, a new foraminiferal qenus from the Tertiary of Born- eco. Leidsche Geol. Mededeelingen, deel VIII, pp. 155-159 (1 plate).
1928. A second species of Biplanispira from the Bocene of Borneo. Leidseche Geol. Mededeclingen, deel X, pp. 82-89.
Vaughan, T. W.
1928. Species of large arenaceaus and orbitoidal Foraminifera from the Tertiary deposits of Jamaica. Jour. Paleont., vol. I, pp. 277-298, pis, 43-50.
1929. Additional new species of Tertiary larger Foraminifera from Ja- maica. Jour. Paleont., vol. 3, pp. 373-382, pls. 39-41.
1929. Descriptions of new species of Foraminifera of the aenus Dis- cocyclina from the Eocene of Mexico. Proc. U. S. Nat. Mus., vol. 76, art. 3, pp. 1-18, pls. 1-7.
936. Helicolepidina Nortoni, a new species from a deep well in St. Landry Parish, Lowisiana. Jour. Paleont., vol. 10, pp. 248-252.
1956. New species of orbitoidal Foraminifera of the genus Discocyelina from the lower Eocene of Alabama. Jour. Paleont., vol. 10, pp. 253- 250 nls. 41-43.
1942. Wocene larger Foraminifera from Barbados, B. W. I., and a cat- alogue of the American species of the Discocyclinde (Abstract). Bull. Geol. Soc. of America, vol. 58, p. 1811.
393 VENEZUELAN FORAMINIFERA: CAUDRI 43
Vaughan, T. W., and Cole, W. S.
1941. Preliminary report on the Cretaceous and Tertiary larger For- aminifera of Trinidad, British West Indies. Geol. Soc. of America, Special Paper, No. 30, pp. 1-120, pls. 1-45.
1943. A restudy of the foraminiferal genera Pscudorbitoides and Vaugh- anina. Jour. Paleont., vol. 17, pp. 97-100, pls. 17-18.
Vermunt, L. W. J.
1927. Geology of the Province of Pinar del Rio, Cuba. Dissertation Utrecht, (also: Geographische en Geologische Mededeelingen, Physio- graphischgeologische reeks, No. 13, Utrecht, 1937).
Vierk, I. M. van der
1923. Hen overgangsvorm tusschen Orthophragmina en Lepidocyclina att het Tertiair van Java. Verhandeiimgen v. h. Geologisch-Mijn- bouwkundig Genootschap v. Nederland en Kolonién, geol. serie, deel VII, pp. 91-98, 1 pl.
Voorwijk, G. H.
1937. Foraminifera from the Upper Cretaceous of Habana, Cuba. Proce.
Kon. Acad. Wetensch. Amsterdam, vol. X1,pp. 190-198, pls. I-III.
”
Trinidad March 25th, 1943.
Manuscript submitted May 16, 1944.—Eds.
We ivAL
\ ” : A 1 At u
i haa a 4e vt in hg i Ta a ails: ray lek Wh 2)
(he rh ny Fe ere | energy a
i u i at VERT NG we f 7 i nh OG fy ¢tO a! ain < a : { a ie. : oa ; ] ; i ; Yelere i ; liv if ;
PLATES
PLATE 1 (30)
R. A. Liddle contributed $50.00 toward expense of plates,
46 BULLETIN 114 396
EXPLANATION OF PLATE 1 (380)
Higure Page
Spanead Ono onb oy choo ming ove)) bl staan Mena eben el oe Sree Mee he et ey
Rock-building element in the ‘‘pseudo-odlithic’’ limestone of San Juan. G.86; 13 x.
2. Yubitorm organisms end 8!) \811(0) Rock-building element in the limestone G.9la; 13x.
3. Ranikothalia, div., Lepidorbitoides cf. planasi M. G. Rutten and
“tubiform odliths” TWSARS BY sea eee
GGL /1G65 5 13) x:
sists 3 xX 5. Ranikothalia cf. antillea (Hanz.), Athecocyclina cf. cookei
(WVaughan)iand)tubiformy oOlat his’? eee eisai ase Oe enna A oe Oe G.91b. 13 X. 2 6. Athecocyclina ‘cf. cockei (Vaughan) .220 2000-2 2 ee
Vertical sections, G.91b; 13 x.
i
* nk Are id ar)
itt
we
Mh F
ay) cine h 2 +) my : ti
a i i er
¥ if . = ‘ oat
|
at
{
; | |
Bi Oy 3
Ww Tia
48 BULLETIN 114 398
EXPLANATION OF PLATE 2 (31)
Figure Page 7.) Hexagonocyclina meandrica, n. Sp. 2 EEE 13
Holotype, horizontal section (center out of focus; compare fig-
ure 9). GAl2Z8> 52) xX. 8. ‘Discecy.clima: jaguerreverel) no (SD) Eee 11
Central part of horizontal section, same as figure 13. Kidney- shaped second embryonic chamber and complete nepionic ring with one of the large chambers over the initial chamber show- ing in this section (other one probably present, but not in the section). G.125¢e; 52 x.
9, Hexagonocyclina))meandrica;’ n: ‘sp, 22 EEE EEE 13 Same specimen as in figure 7 but focussed on central part of
median layer. Small two-ch: imbered embryonic apparatus, two auxiliary chambers and symmetrical development of nep- lonie’\;); spirals? 74/)G.) 1283) 52) xX.
10. Lepidorbitoides cf. planasi M. G. Rutten —.. 16 Vertical section. G.91b; 52 xX. 11. Discocyclina aguerreverei, n. sp. _..------...-----— Maer ah
Central part of horizontal seetion showing kidney- shaped ¢ en- bryonic chamber and complete nepionie ring with two sym- metrical large chambers over the initial chamber. G. 25e; i=) on xX.
Pu. 31, VOL. 28 BuLL. AMER. PALEONT. No. 114, Pu. 2
Sees
My aM nH f mary : fie i A Ree MAL ene mi a Wut
Bopiegin 114
EXPLANATION OF PLATE
Figure
13.
14,
15.
16.
Aihecocyclina cf. cookei (Vaughan) Slightly oblique horizontal
section.
» 3 (32)
Concentric
(wings) faintly and irregularly subdivided into ‘‘chamber-
lets’’; elongated meandric
Discocyclina aguerreverei,
n. sp.
Horizontal section, same as figure. 8.
Lepidorbitoides cf. planasi M. G. Horizontal section showing spiral
Rutten
Gl
lateral chambers.
25¢; 3
G.125¢ ;
arr angement of
chambers round embryonic apparatus and truneated shape x.
of median chambers.
G.125¢e; 52
Ranikothalia antillea (Hanz.) eee Ne Flat variety, vertical section. G.91b;
Lepidorbitoides, sp. ind. Part of median layer.
30
AY Page 14 chambers BIDS < ORXe LOG nepionic : S122 Pe
'Gavse; 52-x.)' > |
ae
52 BULLETIN 114 202 EXPLANATION OF PLATE 4 (33) Figure Page 1%) | Discocyclina ‘aguerreverei, negspe ott Vertical sections (bottom and top left of photograph) and Lepidorbitoides ef. planasi M. G. Rutten, oblique vertical section (top right). G.125ce; 30 x. 18, Athecocyclina ‘cf. cookei’ (Vaughan) 222 2 eee 14 Vertical sections. Lateral chambers especially well preserved in fragment at bottom left of ea ae Geol be TSO <e 19. Ranikothalia cf. soldadensis (V. and C.) — 23 Peripheral vertical section showing a very. ‘elaborate. marginal plexus but for the rest solid walls pierced by diverging bun- dles of vertical canals only at the intersection with the septa. Gals3r 3 Ole 20;; “Athecocyclina cf; ‘cookel (Vaughan) 223 Eee 14 Oblique section. G.91b; 30 X. 21. (Ranikothalia, ‘antillea’/\(Hanz)) 220 ee 22
Oblique and peripheral vertical sections showing solid walls, marginal plexus and double structure of the septa (intersep- tal canals). G.s.s.; 30 X.
we ees yee | ee Te Ne a ee ualies beat) 4 u ia Th hel ( : y I
ny
ot a at r way et ed
, ' Wipe teal MoCo ei t Wty 7a lal thy ' i ie 1 i } He yin My a , i Wal r, nik! i Pahari i i Thy AX + im y Hvar 7 ) NW ¥ tr nn f r ay Uyaas itt i ‘ / ! I eaiet 1 \ i i \ j i i i ‘ h i ( yh) a é i ni! ney j Ae fi \ : Hin Fay i » ii iw \ iy) ii h i i} / i hy i LANE AD WU i Ay I i | i v yi | i mt / ; Ae i i f tani i o I \ R) My f 1 iM 1 l = t T 1 <I as | i j / ij Avi) Mii) e
; edn ca - ys f Tt aa vi rete, ait
54 BULLETIN 114 404 EXPLANATION OF PLATE 5 (34) Figure Page 22. Ranikothalia jtobleri: (VV. and ¢,)) 2) Eee 22 Vertical section of very flat specimen with evolute final whorl. Solid walls, well-developed marginal plexus and a few verti- eal canals in the axial region. G.s.s.; 30 X. 23. KRanikothalia antillea,(Hanz.) 0 Ee 22 Vertical seetion of typical thick lenticular form, Solid walls, marginal plexus, vertical canals in axial region. G.125e; OX Z Ranikothalia soldadensis (V. and C.) 2... Ne 23 Marginal part of excentrie vertical section. Solid walls, high- ly developed marginal plexus and wide vertical canals in cen- tral region. G-s.s.; 30 xX. Be Ranikothaliay antillea, (Hanz) 0 2 Ee 22 scentric horizontal sections showing the low whorls and the solid stiueture of the walls. G.153; 30 x. 26. Ranikothalia soldadensis (V. and C.) 22, 23
small specimen (or perhaps ‘‘R. tobleri (V. and C.) forma B’’), oblique horizontal section. Wide whorl of round- topped chambers that are completely med with a thin solid
vall separating the chamber cavity from the maze of canals in
the marginal plexus. G.91b; 30 X.
BuLuL. AMER. PALEONT. No. 114, Pu. 5
PL. 34, VOL. 28
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INDEX TO VOLUME XXVIII
Note:-Light face figures refer to the volume paging and not to the paging of the separate bulletins. Heavy face figures refer to the volume
plate numbers.
A Abderospira aldrichi_. 25 324 Cnupolanay 324 Acleistoceras jonesi_ Suen 18 Actezonella limestones 173 Actzonellen-Rudisten- Kaliksteine = 171 Actinoceras arcuanotum 2 68 kentuckiense —_.------ 69 Actinomorpha. 30, 36, 53, 58, 62, 64 Agoniatites nodiferis ie lS: WESSON 17 Aljlumettoceras: 2. 39, 69 Alpenoceras occidentale 58 ubrenelay): Le ee 58 Amotape Range —... 166, 168 Amphicyrtoceras __.... 88 Pemulitimum — 35 Amphistegina cf. NO EZtEIS Olu anes 377 Ampullina breccia - 16, 175, 255 CUM ae ee 16 175, 256 oviformis eee 255 tortuga __- 22 175, 256 Anaspyroceras” 105, 110, TG ae ale45) Acraitslinniy eee 13 202 Anchura pacifica eeeeenr 2]! 250 Anomia, sp. 174, 198 AMG C-Onia.) Se. 213 Aphrodina cf. auca 174, 213 AUUUS EIS) een en BLS pacifica 14 174, 212, 215 regia _._ ae 213 speciosa = ial 174, 214 tippana eae ee 213 Apsidocerds. 2 2 25 Arca equilateralis — .. 193 Archiacoceras - aU), As orags Gv! subventricosum _ 5, §, Bue (160 ventricosum 40 Architectonica acuta 313, 316,7318 canaliculata 2 Bless shalls) elaborata —__ Sst35 Slbe 320 meekana ___ 25 314, 316 meekana splendida 318 lie carey Tay eee ene 315 OT alto green ene eee 313, 320 Saimiay a eee ee ee 821 texcarolina _ 25 319 Gextilinaye eee wae Oy, Armenoceras, n. sp. 87
DUpas 3) bile 535) 0D Asterorbis aguayoi___ 380 havanensis 380 TNA CCIG eas ee ee 380 TOOK eo ee ee 380 Athecocyclina cf. cookei 30, 32, 33 357, 364, 376, 380 soldadensis —_ 365, 374, 378, 380 stephensoni —._- Zz 365, 377 ACE Dae 85 Contracts. 150 reticulariss 100 Athyris angelicoides._ 154 coloradoensis ——____ 154 Danviulaye see 144 ViltrevG eye eee eee 7 146, 154 Aniloporay ene 16 Austrosphenodiscus sees 266 peruviana eps 7-1: | 267 Austrosphenodiseus-_ Paciceras shales_ 173 B Baculites cf. anceps __ 262 argentinicus = 263 lyelli _ 23 176, 262, 264 Onna tus) ye eee 262 vagina een eee 262 vagina cazadorianus__ 263 zones foe) BARS Vis. LD Baldwin, HE. M. On Three Forks fauna
of Idaho Barrandeoceras Deseier Ocer ge - Beloitocers ; Bick: eee bickmor- eanum Biplanispiray Bollocerach == eee Bonellitia ulmula Borelis cardenasensis Brachyeyeloceras TIAGO, SS Breviarea perovalis peruviana 22s Sub Oval dS eee Brevicocerasy = oes pompeyense Bulan drichiis Bullina chipolana Bumastus
73, 108,
VOLUME
C
Calliostoma claiborn- Shi Ea oly) eens soot 26 Calyptrza aperta | 2352 cho puleolus! =e trochiformis Calyptraphorus hopkinsi Camagueyia perplexa 27 Camaroteechia centracta Alb bO Stine nordeggi _- CLAS ue 1p SI eee ON ES ?Camerina cubensis —— dickersoni
Onde
MUA Ghee eee eee pellatispiroides ery vermunti Cancellaria quadrata _~ ulmula Carbactinoceras —__--_----- Cardita beaumonti —— P Cardium ? abnormalis
Drugcent ae pla
caudatum
SSO MDa eee
mellisum
pROcenuMy = eee Carolia parinensis Catoraphiceras
lobatum :
@arrdati@ Ne. Bo
On Foraminifera from
San Juan de los
Morro Sees na ewe Cedarvilloceras Centroceras mareel-
lense) ees eras Centrocyrtoceras
mozolai
rotundum Cerithium
ebiniis# ==
hispidum 222
injaugumeatwimn Cerros de Aspereria __ Ghetetes sy wile Wis ee es CGharamValley ses Cibicides precur-
SOUS pe ee Clavulina shales sees Cleiothyridina devonica Clite ndoceras ain Coahuilites peruviana 1 24
sheltoni Collet WS:
ams
and. Bermudez, P.
248,
175,
146,
146, 146,
370, 370,
370, 370,
174,
174,
107,
1b;
166,
308 311 249 248 254, 335 150 146 150 150 144 380 380 369 372 380 323 323 ual 263 208 210 211 210 211 209 234 125 107
355 124
18 75 75 75 245 241 245 245 169 146 168
385 DUELS
146,154
108,
J.
122 267 267
XXVIII
On Cuban Eocene foram Feneras=— Bay 9! Coleolus ac iculatum eat, erenatocinctum —— Conulites americanus - Conradoceras — Coptostoma rameum 1 25 Ubeehbokehoo) eee ay Corbicula meridiona-_ his ee dg seid ek oP) (9 | pullastra oa aM NE i ae Corbula broggii Ober ew Crisposcala crispa failianum Cryptasterorbis cuben- Sig) yore he ee Ctenoceras Curtoceras) Cyclendoceras
174, 175,
104,
Cycloceras 103, 104, 106, 108, 123,
24 manchuriense Cycloceratidz Cycloclypeus Cymbophora ashburnerii Cyrtina Cyrtoceras annulatum _
conoldale.
subannulatum ~~ Cyrtorizoceras __._ Cyrtospirifer animasen-
BG) oo et ee ee
disjunctus
monticola
Wwinlitn'e yin) eee
whitneyi animasensis
Dalmanitess = = Danaoceras (corrected) Dania curasavica —_— “i Dano Cerasi eee subtrigonum Dawsonoceras zquilonare Pema americanum — bridgeportense
NV Attly See eee
nodocostatum —__ Dictyoconus bel ere, anes ae
americanus 29
32,
25,
Halil
85,
88,
85,
36, 51,
=.= ROA OS
83,
88,
Diestoceras eee eet Dyihowine) eee sealare
Diseoceras _..._- at
Diseocyclina aguerre- verei
Bile Bis see
tae
é 307, 361,
barkeri Rel ui ce blarnpiedie — =e bullbccoky 22 == COOKE ieee ese ee CRASS ge fe 2 a seed Loe 2 cristensis grimsdalei weaveri weaveri parvipapillata Discosorus Dolorthoceras Dowlingoceras Dvgehnoceras) 22s r Wy Seino cenrasy = es E
Eetinochilus texanum cherokense ee lenabicy 2 ee eee
wleusoceras =
Birodoceras indianense n. sp.
EKoannwlaria eocenica Pat
Eeconuloides wellsi- 27
Eodictyoconus cubensis
Zep 28s 29
Endoceras Annalara ve TENORS IMIS)
Endoplecteceras —
Horizoceras platyeeroides ae Lees 5
Eospyroceras 110, lle
Hotriptoceras minutum 5 68,
Epitonium failianum 26
meglamerie _....._ 26 Hskimocenas; 22.0 faa
ome alleteressse linac Eskimoceratide :
Euomphalus BTS mene Miner
eurekensis Eutrockus elaibornian- abe” ta ee Eee A Exoeyrioceras es Exogyra ponderosa F ? calappa — culatus
Fasciolarin Faunus auri sechurna : Flower, R. H. On tissue remn
i
AReS ii
362, 361,
31,
63, 84,
340,
Rayonnoceras - On New York Devon- ian Werneroceras _. On Gonioceras from
\WabaerinenGy (ie
On actinosiphonate
cephalopods) 2 =
On new Ordovician
cephalopods _._..
On Silurian cyrtoconic
cephalopods:
On annulated orthocera-
Cones; 2.5.2 Foersteoceras._ 32, 65, alate
Fusinus ? corbis __ 16 ESUSRIS Cibneiibige teers newberryi
Geisonoceras teichert _— Geisonoceroides — Genera proposed by ‘Shimi- ZAU\ EMnol TONoe Wea) sae Geology of Paita Penin- Sula eae eae Gervillia aviculoides - MTCELGATIS yee ua Gigantoceras, == === Glaueconia cordalis _ 22 Glorioclava inea ___ 19 Glossocardia stephen- soni Glosscphora obesa Gomphoceras Mesure Gonioceras anceps angulatum Ss chaziense. == groenlandicum ___. Noltedahi ips see hubbardi aR AT aad Sie py
Scéidentale ard Oe eta occidentale homerense wullfi Gorbyoceras —__.._ Climbornie =e aes Graciloceras, ee longidomum ~~. 4 Granosolarium meek- aniaeees 25 meekana “splendida Onrnataty ese mek eae LEXCanrOlinay = sen 25 Gunteria floridana Gyronedyceras validum Gyroceras inelegans Gyroscala meglameri-
AON 116.
12,
120,
VoLUME XXVIII
Haminea aldrichi Hammeloceras Hammelloceratide —.— Harrisoceras ignotum _ lenmelenis ey yee monocameratum obstructum orthoceroides reevesi Helicoceras Helicolepidina —_....-.--.-- nortoni SUT aU S ieee nnn Helicostegina dimorpha Helix amarula Heracloceras abruptum elnodifies we sane Hercoceras Herkimeroceras Heterospira .—.— Heterostegina operculin- oides) == Hexagonocyclina eristensis meandrica Hexameroceras uu ecacabitorme 22222 == Hipponix pygmzeus sylveerupis ee vagus —..... N26 Uippurites cornupas- toris Lalbhopoylsy | erate Hypospyroceras Hystricurus
_ 31 357,
Inecacardium mellisum 12 NeanopsiSwe acariformis Tetley 4 Teanotia re Ee SLY D0 ae ea Noe Ja ee DACIICA ewes eg Tddingsella Satie Nddinesiae 222 ee Se “Tnoceramus” - amie Inoceramus balticus Mie cripsi pureed sad eripsi radians CEU SAMUS ie ee TCU ANS yee eee SPAS se os ee 8 Spe Bese 8 Inversoceras
363,
MAO 1G, wea,
388,
36,
362, 376,
K Kayoceras” 223) = 88 Keioniocerash 89, 117 ef. scammondi —-_- 87 Ci. «Strix 87 Korenoceras) oe tire 21 L am Mies ame Eels yal, ales) Lapeirousia nicholasi- 206 Latirus tribulus —._ 22 176, 258 Laureloceras cumingsi 5 83, 97, 98 INOnwenObE ee Oy, OE) nashvilllen'se) 2-2 OD eo mmoo kecanos pita 108, 122 Lechritrochoceras desplainense __.-. 88 waldronense a 86 Legumen peruvianum. 13 174, 216 Leirorhynchus cf. athabascense ____ 7 isl dunbarense 2225225" 146 ef. dunbarense __. 7 151 jeffersonense _.._._- 146 Iban etsy) elk es ae 17 madtsonense 146 madisonense gibbo- SUIT eae eee eee 151 utahense ventricosum 146 ef. waleotti mei 151 Le pidocyclina cedarkey- sensis __ wal 3889 aft. cedarkeysensis” sete 388 claibornensis 389 PAVIOS ct feet ne lle Rshee tewnn ee 390 pustulosay= es wees 389, 390 GODIN eri 2 a ee oee ee 390 Ghoebrimibayeis)) omens 389 subslobosay cls ee 390 undosa Riverine! 390 yurnagunensis 390 Lepidorbitoides 387 aguayoi 380 cubensis - 380 havanensis 380 macel pa) ae 380 macgillavryi- 380 TORUG MUO MALY cen kee ec 380 palmeri - 380 ef. planasi 30, 31, 32 357, 366, 376, 378 rooki 380 Tutbenah | 2 ee 380 rutteni armata peat 380 * T.eptedesma chillen-- SIG eae ee een, 146, 155
408
Leurocycloceras buche rie eee ee feanklinense ae Ch MaAraArense ese
TEV ANN OMCs es eee
Linderina L
Lissapiopsis unicarinata
Lopha
Lower Breccias
Loxopteria -____
Lunulicardium marcel-— lense
yaa conchae
261,
Macleurina logani Macrodonax peruviana 8 Mactra ashburnerii Mal Paso formation _ Mandaloceras wabash- ense Marcrochilina Marssonella oxycona -.. Meandropsina rutteni Melanatria medialis 19 Melania winteri Melina woodsi Meristella cf. barrisi _— Mesalia fasciata UNG) peste sew Metarmenoceras ~ aod te Metasyproceras Saya aie ally M ficheli MOCELAS Eee ee SOU ISG ENT ps ee em one SOL Minranoceras) = =) 30; subturbinatum Miscellanea antillea Matej = see eee TeUIIUIEY ee soldadensis) 222 Stam pie eee tobleri os ove eee Mitroceras __.. ae Monte Grande shales” oa Montyoceras titaniforme Minlinolde sea eaa chica
ana 8 174,
175,
175,
369,
Nzdyceras “Nautilus”
oceanus -____
122,
INDEX
126 100
85
87 104 342 259 199 173 148
16 22
23 220
409
Negritos shales Neocycloceras ———_______ obliguumy === Nerinza inauguratum _ Nerita jayanca umzambiensis Neumatoceras TUG ELT Se IN(OCbbAENDV OnE) a Costatus =.= aes nodosus Nummulites! 52 nuttalli nuttalli con kohaticus sindensis thalicus con gwyne _
O
175,
54,
Olsson, A. A. On Cretaceous of mabe Peru Omphalocyclina macro- pora Oncoceras seeleyi Oocerina Oonoceras __. es Operculina bermudezi a eatenula sindensis Operculinoides caten- ula Orbitoides apiculata —__ browni palmeri Ormoceras ~ ne, Sp: Onthocerads; ee £ amycus anellum annulatum arcuoliratum bilineatum clathratum crotalum gorbyi hammelli olorus
rugosum Simulator ese teretiforme Le tin G geen eee Orthophragmina crassa
176
TYNAN Cae pee ee Orthostrombus = TOrtusens iS) 22 se Ostrea palpa -... sechura stappenbecki Ovoceras oviforme Oxygonioceras wabashense
Pachendoceras Pachyphyllum Paciceras! _._ SENG een ee Daciiicum 22 Paita Cretaceous Paleocycloceras —— Palmer, Ko Vi. Ww: On Claiborne Hocene gastropods Panenka aff. Panope frailia Paraconradoceras Tgulelatesh Aaa et dos- Sanco SIG ees endymion
88 24
ventricosa il
Parinana A al americana Lg Parinomya parinensis — Patella cornucopia Pedalion woodsi —..---.- Pellatispira Mat Ly eee crassicolumnata Bene glabra inflata irregularis maderaszi matleyi orbitoidea rutteni _— Pellatispirella Pentameroceras byronensé, --. : CUMMINS) eee een 2 depressum rarum Perigrammoceras__. Periploma nermeta _~ Peruarca : Ber cat pectunculoides — Perucardia Jus bruiggeni) ws Perustrombus tortugensis wheeleri
-antillea
VOLUME
vane
386 253 253 174, 198 174, 199 174, 199 33 18 32 87, 99
a
108, 122 149 268 270 6, 289
170 , 122
307 16 222
34
266 266 265 247 248 234 310 195 387 371 371 371 371 371 369
174, 368,
369, «
92, 88, 92, 94 93, 124, 174,
174,
175,
XXVIII
Peruvia Mess Le lates Phragmoceras SAT LIVES GU eae bicinctum ey projectumy=— Bi rsemocensilcs subven- tricosum am Platyelymenia ameri- cana a petersenii! f Plotia lina Portenocends gs ===. Previcarya peruviana 19 Productelia, sp. cf. coleradensis Proteus haldemani 2) Prolobites-Platycly- menis-Stufe att Proporocyclina tobleri_ j Protocycloceras ROSS Tay ENO lan varek 1 Proteki Jonoceras, sp. aff. myrice Protophragmoceras Pscudeskimoceras Pscudocuculiaa greg-
116,
OTe este oie tae ae
Daitaniayy eee ser see Pscudomeiania sim-
plex i9
Pseudorbitoides israel- skii a a eae trechmanni~ ve
Pseudorbitolina cuben- sis ae a eo ea mar the NORM
Pseudophragmina “tob- leri celled Gr actareteaten
Pugnax, sp. Basen ean 17 LGU S = Ses ee ae minutus pons); i
Pugnellus ? eypreefor- mis See ec Fate SS Rae densatu!s\. = = ee hamulus tiumidus, 2222 x
Pulvinulinella obtusa 2
Pyrazus pentagonatus _ peruvianus _._._.. 20
pyramidatus: ===) 5s
Quiriquina beds
R Radiolites nicholasi —.- sandstones) 222022 oe Ranikothalia antillea
34,
118,
ize,
84,
146,
175,
164
208 L79
367, 387
30, 32, 33, 34, 357, 370, 372, 376
bermudezi mutéalli - bane. Saad SUMGCNSIS: 225-5. soldadensis
thalica eee SODIGT IE 34 357, 371, Rayonnoceras passleri buffraloense girtyl malotti solidiforme vaughanianum Receptaculites occiden- talis Retieularias Sp... Rhinotamides aoe 20 Rhipidomella vanuxemi Rhombopsis orientalis microstriatus Richardsonoceras Rimella texana plana _ Rostellaria plana Roudaireia nuressensis briiggeni ae 1D)iebti” ae aeeat eee intermedia _. = jamaicensis peruvi- ana OIE NEY Te eet) Ruedemannoceras stonense
Salina formation Saman sandstone Sauvagesia peruviana Scabrotrigona Seala) pretiosa 2.2 Scalaria commutata Sealpellum : Schizophoria striatula australis Schroederoceras Schuchertella chemung- ensis arcuostnlata y= 7, Sechura Miocene... Sechurina BVPI M IIS: Le Ds Sechuritella —.. 7 chacapoya terebracincta Septifer acutus Solariaxis
Solarium eanalicula- tym delphinuloides
175,
39,
174,
174,
174,
144,
146,
175, 175,
INDEX
3871 meekanum
371 ornatum BSED oad SI oe:
3871 Spbaerulitez. nicnolasi ®phenodiseus le
377 pleurisepta peruviana
371 Spiriter disjunctus ani-
377 RASSNISIS ye eek anne
10 Spirifer raymondi __ 7
ial utahensis
13 whitneyi : pal
12 whitneyi monticola _
12 Spiroplectamina grzy-
ila bowsidi ze
12 Spyroceras
Son 103, O04:
23 clintoni a 144 crotalum ae: 239 ELC Ze ene eee eae 148 Dima eee ee 2517 middlevillense PRP 257 oppletum bbe Ura
98 orientale Eyaee 322 POLE ee ee eae 3822 thestor AES hie 165 ruedemanni __.
203 Spyroceratidze : 203 Spiroclypeus ee 203 Stalioa agnia 19 203 deschiensi ; Stereoplasmocerina 203 Stereetoceras aS fee ee 202 Striacceeras typum 9s Striarea thielei 22 Strombus canalis Styli dlina fissurella 167 Subspyroceras s 168 Suleoperculina ee 206 dickersonij as 200 Sympanotomus murica- BU) aes ee 310 “yringothyris aN 176 T 147 Talara shale i ae 78 Vectus tschudi 1G Tellidora burneti peruana 13 150 TYellipiura 168 peruana i3 215 Tetrameroceras « discrep- 215 anise ea ae 234 bellatulum m 235 bicinetum 235 deshayesi 195 faberi ils 8 312 UME EIA ON) | te ee 247 rpayeKON lige PGE | Ce ye loveni 2. — ee 313 problematicum wae 321 TAMTO SUrueer ee eee
146,
175,
NNN hoe
VoLUME XXVIII
WeCUS ies eee ee Thianassa coconia — 20 Thiara aldrichi _.__ 26
SCaDlan ee eee
175,
Tofangoceras -... 105, 111, 120,
huroniftormie)) 2022 — Mofanivocerina ss AMopseancilleysy | Se JOSUNALOE, oe iL Morno Caras) jee Torreina torrel 2 2 Mortucardia eee eee stephensoni _-_-..- 24 Tortucerithium textilis MOWGU a es ees eae res rep LOCenas meee ure wesee 110, Trigonia bartrami ——— erenulata essa eis
DALV Op tet Meee SVOVET: Siena eee subcrenulata o2 2 tocaimaaniay so es
Tripteroceras -_... CE
Mroeholitesie eee amimeonius Ta ARR Canadensis. cireularis Bese iy Tig, oes ae ee ee PapeNles a aeceerte ne eee a SPACMIS yas eee ONO. internastriatus TMINUS CWS) se planorbiformis _.--.- ruedemanni ...... 5
Trocholitoceras we
Trochus. conus) 2 perspectivus: 2
Trocotaulax elegans 20
Tubiferoceras Bld) gilberti LiTre aC ee
“Tubiform odliths” — 30
Rurbow scalars: ise
Turritella bartsia_.. 22 bosworthi rales he Bie Cel ba ee aS chira Mee) AR Se Gesolatal ssa ae a2 Gielen somite ses senate rb go iy e2y pile he 20 lama LeU ake OPAL by lissoni nasuta ay : parinensis 22 18 precincta
106, 175,
174, 169, 116,
174,
78,
68,
175, 175, 175,
175, 175,
95 pLeching) = sen 17 175, 230 238 prelissoni = 23 175, 231 311 Tey gf? Oph a ere eR ALS 25 321 312 SADOS@it = ote 17 175, 229 1238 SOAneSaAn a yee een 230 121 wechesensis, == == 321 124 Turrilites peruvianus 24 176, 265 250 251 U
16 Upper Breccia zone __— 179 380 Uranoceras 85 204 204 Vv
Vaginoceras oppletum 48
178 Valeouroceras 30, 36, 38, 43, 64, 66 123 Dp OWA Tee A YAO Asha 201 cyclops. PSHM ay 20, ey 201 ObeSum eae 4 46 200 qecilenri Ls 4 47 2015) cia seeleyil = 4 48 201 roy oir Wena ae me 4 49 201 SID ea jeeilie ea 4 50 2010 Vaughaninas ss. 380 201 Cubes) sie 380
SOPAVienUS sallcay eee eens 213
76 Subsulca ta sss 215
76 Verticoceras -...--....-- 33
CHL Erect eens 18
77 Vicarya fusiformis —___ 247
77 Sapp hoy ee ena 248
77 Virgoceras cancellatum 100, 84
81 Volsella cerva _.. 24 195
i ovolutay incase 16 176, 261
77 purpuritormis) == 259
77 Volutilithes ef. crenulu-
78 Tal ek ek cl te 260
76 Volutilithes radula —_ 261 308 Vclutocorbis meridion-
313 Ci DISSRR eee eee rs | 16 176, 260 238
89 WwW
87 Walcottoceras —.... 108, 121, 125
87 Werneroceras plebi-
374 LOGEC = eee 1 14, 19 309 Westonoceras —.......__ 42 233 deckerime.2 ue ee 25 234 Wetherbyoceras — 31, 85, 238.0 64 230 Wichitoceras decipiens 78 230 “WioodSaliay: ss seen 375 232 Woodsalia negritensis _ 228 235 paitanay — ease 18 175, 227 231 paitana robusta __ 18 175, 22 228 Worthenoceras —_. 88 232
318
233 XY
OS Vevasiliay «eee en nee ee 167
412
TONE 0 id aera ey fs ga a Cees Pet Siem
Re itt
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